SYNOPSIS
cc <source> -ljimor
jimsh [<scriptfile>|-]
jimsh -e '<immediate-script>'
jimsh --version
jimsh --helpINTRODUCTION
Jim Tcl is a small footprint reimplementation of the Tcl scripting language. The core language engine is compatible with Tcl 8.5+, while implementing a significant subset of the Tcl 8.6 command set, plus additional features available only in Jim Tcl.
Some notable differences with Tcl 8.5/8.6/8.7 are:
-
Object-based I/O (aio), but with a Tcl-compatibility layer
-
I/O: Support for sockets and pipes including TCP, UDP, UNIX-Domain sockets and IPv6
-
Integers are 64bit
-
Support for references (
ref/getref/setref) and garbage collection -
Builtin dictionary type (
dict) with some limitations compared to Tcl 8.6 -
envcommand to access environment variables -
Operating system features:
os.fork,os.uptime,wait,signal,alarm,sleep -
Much better error reporting.
infostacktraceas a replacement for $errorInfo, $errorCode -
Support for "static" variables in procedures
-
Threads and coroutines are not supported
-
Command and variable traces are not supported
-
Built-in command line editing in interactive mode with autocompletion and hints
-
Expression shorthand syntax:
$(…) -
Modular build allows many features to be omitted or built as dynamic, loadable modules
-
Highly suitable for use in an embedded environment
-
Jim does not convert backslash-newline within braces (in order to preserve accurate line numbers)
RECENT CHANGES
Changes since 0.83
-
aio- support for configurable read and write buffering -
Add support for
packageforget -
Add
aiotranslationsupport (and fconfigure -translation) -
execTIP 424 - support saferexec |syntax (alsoopen "|| pipeline…") -
New
lsubstcommand to create lists using subst-style substitution -
vwaitnow accepts a script argument -
Add support for
os.umask -
Add
taintsupport for improved data security -
Improved API for creating C commands with
Jim_RegisterCommandfor arg checking and usage -
New
infousageto return the usage for a proc or native command -
New
infoaliasesto list all aliases -
exprsupports new=*and=~matching operators (see EXPRESSIONS) -
aiogetssupports-eoland-keep
Changes between 0.82 and 0.83
-
infoframenow only returns proc levels -
stacktraceis now a builtin command -
The stack trace on error now includes the full stack trace, not just back to where it was caught
-
Improvements with
aio, related to eventloop and buffering. Addaiotimeout. -
Add support for hinting with
historyhints -
Support for
procstatics by reference (lexical closure) rather than by value -
regsubnow supports -command (per Tcl 8.7) -
Add support for
lsort-dict
Changes between 0.81 and 0.82
-
trynow supports trap to match on errorcode -
Add support for
socket-async -
The handles created by
socketptynow make the replica name available via filename -
infoframenow returns a (largely) Tcl-compatible dictionary, and supports info frame 0 -
vwait-signalis now supported -
./configure now defaults to --full
-
New
timeratecommand as an improvement overtime, somewhat compatible with TIP 527 -
Add
ensemblecommand and support fornamespaceensemble(as an optional extension)
Changes between 0.80 and 0.81
-
TIP 582, comments allowed in expressions
-
Many commands now accept "safe" integer expressions rather than simple integers:
loop,range,incr,stringrepeat,lrepeat,pack,unpack,rand -
String and list indexes now accept integer expressions (STRING AND LIST INDEX SPECIFICATIONS)
-
loopcan now omit the start value -
Add the
xtracecommand for execution trace support -
Add
historykeep -
Add support for
lsearch-indexandlsearch-stride, the latter per TIP 351 -
lsort-indexnow supports multiple indices -
Add support for
lsort-stride -
opennow supports POSIX-style access arguments -
TIP 526,
exprnow only allows a single argument (unless --compat is enabled)
Changes between 0.79 and 0.80
-
regsubnow fully supports\A -
Add
socketptyto create a pseudo-tty pair -
Null characters (\x00) are now supported in variable and proc names
-
dictionaries and arrays now preserve insertion order, matching Tcl and the documentation
-
Add
dictgetwithdefault(and the aliasdictgetdef) per TIP 342 -
Add string comparison operators (lt, gt, le, ge) per TIP 461
-
Implement
0dradix prefix for decimal per TIP 472
Changes between 0.78 and 0.79
-
Add
filemtimeusfor high resolution file timestamps -
aionow supports datagram Unix-Domain sockets -
Add support for
aiolock -wait -
Add
signalblockto prevent delivery of signals -
Add support for
filesplit -
Add support for
json::encodeandjson::decode -
aiottynow allows settingechowithout fullrawmode
Changes between 0.77 and 0.78
-
Add serial/tty support with
aiotty -
Add support for jimsh -
-
Add hidden -commands option to many commands
-
Add scriptable autocompletion support in interactive mode with
tcl::autocomplete -
Add
aiosockopt -
Add scriptable autocompletion support with
historycompletion -
Add support for
treedelete -
Add support for
deferand $jim::defer -
Renamed
os.waittowait, now more Tcl-compatible and compatible withexec... & -
Closing a pipe open with
open|...now returns Tcl-like status -
It is now possible to used
execredirection with a pipe opened withopen|... -
Interactive line editing now supports multiline mode if $::history::multiline is set
Changes between 0.76 and 0.77
Changes between 0.75 and 0.76
Changes between 0.74 and 0.75
-
filecopy-forcehandles source and target as the same file -
formatnow supports%bfor binary conversion -
lsortnow supports-uniqueand-real -
Add support for half-close with
aioclose?r|w? -
Add
socketpairfor a bidirectional pipe -
Add --random-hash to randomise hash tables for greater security
-
dictnow supports for, values, incr, append, lappend, update, info and replace -
filestatno longer requires the variable name -
Add support for
filelink
TCL INTRODUCTION
Tcl stands for tool command language and is pronounced tickle. It is actually two things: a language and a library.
First, Tcl is a simple textual language, intended primarily for issuing commands to interactive programs such as text editors, debuggers, illustrators, and shells. It has a simple syntax and is also programmable, so Tcl users can write command procedures to provide more powerful commands than those in the built-in set.
Second, Tcl is a library package that can be embedded in application programs. The Tcl library consists of a parser for the Tcl language, routines to implement the Tcl built-in commands, and procedures that allow each application to extend Tcl with additional commands specific to that application. The application program generates Tcl commands and passes them to the Tcl parser for execution. Commands may be generated by reading characters from an input source, or by associating command strings with elements of the application’s user interface, such as menu entries, buttons, or keystrokes.
When the Tcl library receives commands it parses them into component fields and executes built-in commands directly. For commands implemented by the application, Tcl calls back to the application to execute the commands. In many cases commands will invoke recursive invocations of the Tcl interpreter by passing in additional strings to execute (procedures, looping commands, and conditional commands all work in this way).
An application program gains three advantages by using Tcl for its command language. First, Tcl provides a standard syntax: once users know Tcl, they will be able to issue commands easily to any Tcl-based application. Second, Tcl provides programmability. All a Tcl application needs to do is to implement a few application-specific low-level commands. Tcl provides many utility commands plus a general programming interface for building up complex command procedures. By using Tcl, applications need not re-implement these features.
Third, Tcl can be used as a common language for communicating between applications. Inter-application communication is not built into the Tcl core described here, but various add-on libraries, such as the Tk toolkit, allow applications to issue commands to each other. This makes it possible for applications to work together in much more powerful ways than was previously possible.
Fourth, Jim Tcl includes a command processor, jimsh, which can be
used to run standalone Tcl scripts, or to run Tcl commands interactively.
This manual page focuses primarily on the Tcl language. It describes the language syntax and the built-in commands that will be available in any application based on Tcl. The individual library procedures are described in more detail in separate manual pages, one per procedure.
JIMSH COMMAND INTERPRETER
A simple, but powerful command processor, jimsh, is part of Jim Tcl.
It may be invoked in interactive mode as:
jimshor to process the Tcl script in a file with:
jimsh filenameor to process the Tcl script from standard input:
jimsh -It may also be invoked to execute an immediate script with:
jimsh -e "script"Interactive Mode
Interactive mode reads Tcl commands from standard input, evaluates those commands and prints the results.
$ jimsh
Welcome to Jim version 0.73, Copyright (c) 2005-8 Salvatore Sanfilippo
. info version
0.73
. lsort [info commands p*]
package parray pid popen proc puts pwd
. foreach i {a b c} {
{> puts $i
{> }
a
b
c
. bad
invalid command name "bad"
[error] . exit
$If jimsh is configured with line editing (it is by default) and a VT-100-compatible
terminal is detected, Emacs-style line editing commands are available, including:
arrow keys, ^W to erase a word, ^U to erase the line, ^R for reverse incremental search
in history. Additionally, the h command may be used to display the command history.
Command line history is automatically saved and loaded from ~/.jim_history
In interactive mode, jimsh automatically runs the script ~/.jimrc at startup
if it exists.
INTERPRETERS
The central data structure in Tcl is an interpreter (C type Jim_Interp). An interpreter consists of a set of command bindings, a set of variable values, and a few other miscellaneous pieces of state. Each Tcl command is interpreted in the context of a particular interpreter.
Some Tcl-based applications will maintain multiple interpreters simultaneously, each associated with a different widget or portion of the application. Interpreters are relatively lightweight structures. They can be created and deleted quickly, so application programmers should feel free to use multiple interpreters if that simplifies the application.
DATA TYPES
Tcl supports only one type of data: strings. All commands, all arguments to commands, all command results, and all variable values are strings.
Where commands require numeric arguments or return numeric results, the arguments and results are passed as strings. Many commands expect their string arguments to have certain formats, but this interpretation is up to the individual commands. For example, arguments often contain Tcl command strings, which may get executed as part of the commands. The easiest way to understand the Tcl interpreter is to remember that everything is just an operation on a string. In many cases Tcl constructs will look similar to more structured constructs from other languages. However, the Tcl constructs are not structured at all; they are just strings of characters, and this gives them a different behaviour than the structures they may look like.
Although the exact interpretation of a Tcl string depends on who is doing the interpretation, there are three common forms that strings take: commands, expressions, and lists. The major sections below discuss these three forms in more detail.
BASIC COMMAND SYNTAX
The Tcl language has syntactic similarities to both the Unix shells and Lisp. However, the interpretation of commands is different in Tcl than in either of those other two systems. A Tcl command string consists of one or more commands separated by newline characters or semi-colons. Each command consists of a collection of fields separated by white space (spaces or tabs). The first field must be the name of a command, and the additional fields, if any, are arguments that will be passed to that command. For example, the command:
set a 22has three fields: the first, set, is the name of a Tcl command, and
the last two, a and 22, will be passed as arguments to
the set command. The command name may refer either to a built-in
Tcl command, an application-specific command bound in with the library
procedure Jim_RegisterCommand, or a command procedure defined with the
proc built-in command.
Arguments are passed literally as text strings. Individual commands may
interpret those strings in any fashion they wish. The set command,
for example, will treat its first argument as the name of a variable
and its second argument as a string value to assign to that variable.
For other commands arguments may be interpreted as integers, lists,
file names, or Tcl commands.
Command names should normally be typed completely (e.g. no abbreviations).
However, if the Tcl interpreter cannot locate a command it invokes a
special command named unknown which attempts to find or create the
command.
For example, at many sites unknown will search through library
directories for the desired command and create it as a Tcl procedure if
it is found. The unknown command often provides automatic completion
of abbreviated commands, but usually only for commands that were typed
interactively.
It’s probably a bad idea to use abbreviations in command scripts and other forms that will be re-used over time: changes to the command set may cause abbreviations to become ambiguous, resulting in scripts that no longer work.
COMMENTS
If the first non-blank character in a command is #, then everything
from the # up through the next newline character is treated as
a comment and ignored. When comments are embedded inside nested
commands (e.g. fields enclosed in braces) they must have properly-matched
braces (this is necessary because when Tcl parses the top-level command
it doesn’t yet know that the nested field will be used as a command so
it cannot process the nested comment character as a comment).
GROUPING ARGUMENTS WITH DOUBLE-QUOTES
Normally each argument field ends at the next white space, but double-quotes may be used to create arguments with embedded space.
If an argument field begins with a double-quote, then the argument isn’t terminated by white space (including newlines) or a semi-colon (see below for information on semi-colons); instead it ends at the next double-quote character. The double-quotes are not included in the resulting argument. For example, the command
set a "This is a single argument"will pass two arguments to set: a and This is a single argument.
Within double-quotes, command substitutions, variable substitutions, and backslash substitutions still occur, as described below. If the first character of a command field is not a quote, then quotes receive no special interpretation in the parsing of that field.
GROUPING ARGUMENTS WITH BRACES
Curly braces may also be used for grouping arguments. They are similar to quotes except for two differences. First, they nest; this makes them easier to use for complicated arguments like nested Tcl command strings. Second, the substitutions described below for commands, variables, and backslashes do not occur in arguments enclosed in braces, so braces can be used to prevent substitutions where they are undesirable.
If an argument field begins with a left brace, then the argument ends at the matching right brace. Tcl will strip off the outermost layer of braces and pass the information between the braces to the command without any further modification. For example, in the command
set a {xyz a {b c d}}the set command will receive two arguments: a
and xyz a {b c d}.
When braces or quotes are in effect, the matching brace or quote need
not be on the same line as the starting quote or brace; in this case
the newline will be included in the argument field along with any other
characters up to the matching brace or quote. For example, the eval
command takes one argument, which is a command string; eval invokes
the Tcl interpreter to execute the command string. The command
eval {
set a 22
set b 33
}will assign the value 22 to a and 33 to b.
If the first character of a command field is not a left brace, then neither left nor right braces in the field will be treated specially (except as part of variable substitution; see below).
COMMAND SUBSTITUTION WITH BRACKETS
If an open bracket occurs in a field of a command, then command substitution occurs (except for fields enclosed in braces). All of the text up to the matching close bracket is treated as a Tcl command and executed immediately. Then the result of that command is substituted for the bracketed text. For example, consider the command
set a [set b]When the set command has only a single argument, it is the name of a
variable and set returns the contents of that variable. In this case,
if variable b has the value foo, then the command above is equivalent
to the command
set a fooBrackets can be used in more complex ways. For example, if the variable b has the value foo and the variable c has the value gorp, then the command
set a xyz[set b].[set c]is equivalent to the command
set a xyzfoo.gorpA bracketed command may contain multiple commands separated by newlines or semi-colons in the usual fashion. In this case the value of the last command is used for substitution. For example, the command
set a x[set b 22
expr $b+2]xis equivalent to the command
set a x24xIf a field is enclosed in braces then the brackets and the characters between them are not interpreted specially; they are passed through to the argument verbatim.
VARIABLE SUBSTITUTION WITH $
The dollar sign ($) may be used as a special shorthand form for
substituting variable values. If $ appears in an argument that isn’t
enclosed in braces then variable substitution will occur. The characters
after the $, up to the first character that isn’t a number, letter,
or underscore, are taken as a variable name and the string value of that
variable is substituted for the name.
For example, if variable foo has the value test, then the command
set a $foo.cis equivalent to the command
set a test.cThere are two special forms for variable substitution. If the next character after the name of the variable is an open parenthesis, then the variable is assumed to be an array name, and all of the characters between the open parenthesis and the next close parenthesis are taken as an index into the array. Command substitutions and variable substitutions are performed on the information between the parentheses before it is used as an index.
For example, if the variable x is an array with one element named first and value 87 and another element named 14 and value more, then the command
set a xyz$x(first)zyxis equivalent to the command
set a xyz87zyxIf the variable index has the value 14, then the command
set a xyz$x($index)zyxis equivalent to the command
set a xyzmorezyxFor more information on arrays, see VARIABLES - SCALARS AND ARRAYS below.
The second special form for variables occurs when the dollar sign is followed by an open curly brace. In this case the variable name consists of all the characters up to the next curly brace.
Array references are not possible in this form: the name between braces is assumed to refer to a scalar variable. For example, if variable foo has the value test, then the command
set a abc${foo}baris equivalent to the command
set a abctestbarVariable substitution does not occur in arguments that are enclosed in braces: the dollar sign and variable name are passed through to the argument verbatim.
The dollar sign abbreviation is simply a shorthand form. $a is
completely equivalent to [set a]; it is provided as a convenience
to reduce typing.
SEPARATING COMMANDS WITH SEMI-COLONS
Normally, each command occupies one line (the command is terminated by a
newline character). However, semi-colon (;) is treated as a command
separator character; multiple commands may be placed on one line by
separating them with a semi-colon. Semi-colons are not treated as
command separators if they appear within curly braces or double-quotes.
BACKSLASH SUBSTITUTION
Backslashes may be used to insert non-printing characters into command fields and also to insert special characters like braces and brackets into fields without them being interpreted specially as described above.
The backslash sequences understood by the Tcl interpreter are listed below. In each case, the backslash sequence is replaced by the given character:
-
\b -
Backspace (0x8)
-
\f -
Form feed (0xc)
-
\n -
Newline (0xa)
-
\r -
Carriage-return (0xd).
-
\t -
Tab (0x9).
-
\v -
Vertical tab (0xb).
-
\ddd -
The digits
ddd(one, two, or three of them) give the octal value of the byte. Note that Jim supports null characters in strings. -
\xnn -
The hexidecimal digits
nngive the value of the byte. -
\unnnn -
\u{nnn} -
\Unnnnnnnn -
The UTF-8 encoding of the unicode codepoint represented by the hex digits,
nnnn, is inserted. The u form allows for one to four hex digits. The U form allows for one to eight hex digits. The u{nnn} form allows for one to eight hex digits, but makes it easier to insert UTF-8 characters that are followed by a hex digit.
If a backslash is followed by something other than one of the options described above, the backslash is skipped and character following the backslash is treated as a normal character without any special meaning. The Tcl scanner continues normal processing with the next character. For example, in the command
For example, in the command
set a \{x\[\ yz\141the second argument to set will be {x[ yza.
If an argument is enclosed in braces, then backslash sequences inside the argument are parsed but no substitution occurs: the backslash sequence is passed through to the argument as is, without making any special interpretation of the characters in the backslash sequence. In particular, backslashed braces are not counted in locating the matching right brace that terminates the argument. For example, in the command
set a {\{abc}the second argument to set will be \{abc.
This backslash mechanism is not sufficient to generate absolutely
any argument structure; it only covers the
most common cases. To produce particularly complicated arguments
it is probably easiest to use the format command along with
command substitution.
STRING AND LIST INDEX SPECIFICATIONS
Many string and list commands take one or more index parameters which specify a position in the string relative to the start or end of the string/list.
The index may be one of the following forms:
-
integer -
A simple integer, where
0refers to the first element of the string or list. -
integerexpression -
Any "safe" expression that evaluates to an integer. A "safe" expression does not perform variable or command subsitution, but is otherwise like a normal expression (see EXPRESSIONS).
-
For example
1+2*3is valid integer expression, but{$x*2-1}is not. But note that it is possible to use an unbraced expression to allow the Tcl interpreter to expand variables and commands before being parsed as an integer expression. -
e.g.
string repeat a $x*2-1 -
end -
The last element of the string or list.
-
end-integer -
end-integerexpression -
end+integerexpression -
The nth-from-last element of the string or list. Again, a "safe" integer expression may be used in place of a simple integer.
end-3orend-3+2*$n. Normally it only makes sense to use theend-form, but if the integer expression is negative, theend+ form may be used.
COMMAND SUMMARY
-
A command is just a string.
-
Within a string commands are separated by newlines or semi-colons (unless the newline or semi-colon is within braces or brackets or is backslashed).
-
A command consists of fields. The first field is the name of the command. The other fields are strings that are passed to that command as arguments.
-
Fields are normally separated by white space.
-
Double-quotes allow white space and semi-colons to appear within a single argument. Command substitution, variable substitution, and backslash substitution still occur inside quotes.
-
Braces defer interpretation of special characters. If a field begins with a left brace, then it consists of everything between the left brace and the matching right brace. The braces themselves are not included in the argument. No further processing is done on the information between the braces except that backslash-newline sequences are eliminated.
-
If a field doesn’t begin with a brace then backslash, variable, and command substitution are done on the field. Only a single level of processing is done: the results of one substitution are not scanned again for further substitutions or any other special treatment. Substitution can occur on any field of a command, including the command name as well as the arguments.
-
If the first non-blank character of a command is a
#, everything from the#up through the next newline is treated as a comment and ignored.
EXPRESSIONS
The second major interpretation applied to strings in Tcl is
as expressions. Several commands, such as expr, for,
and if, treat one or more of their arguments as expressions
and call the Tcl expression processors (Jim_ExprLong,
Jim_ExprBoolean, etc.) to evaluate them.
The operators permitted in Tcl expressions are a subset of the operators permitted in C expressions, and they have the same meaning and precedence as the corresponding C operators. Expressions almost always yield numeric results (integer or floating-point values). For example, the expression
8.2 + 6evaluates to 14.2.
Tcl expressions differ from C expressions in the way that operands are specified, and in that Tcl expressions support non-numeric operands and string comparisons.
A Tcl expression consists of a combination of operands, operators, and parentheses.
White space may be used between the operands and operators and parentheses; it is ignored by the expression processor. Where possible, operands are interpreted as integer values.
Comments are allowed in expressions, beginning with the # character and continuing until the end of line or end of expression.
Integer values are interpreted as decimal, binary, octal or hexadecimal if prepended with 0d, 0b, 0o or 0x respectively. Otherwise they are interpreted as decimal by default. (Jim Tcl does not interpret numbers with leading zeros as octal.)
If an operand does not have one of the integer formats given above, then it is treated as a floating-point number if that is possible. Floating-point numbers may be specified in any of the ways accepted by an ANSI-compliant C compiler (except that the f, F, l, and L suffixes will not be permitted in most installations). For example, all of the following are valid floating-point numbers: 2.1, 3., 6e4, 7.91e+16.
If no numeric interpretation is possible, then an operand is left as a string (and only a limited set of operators may be applied to it).
String constants representing boolean constants
(0, 1, false, off, no, true, on, yes)
are also recognized and can be used in logical operations.
Operands may be specified in any of the following ways:
-
As a numeric value, either integer or floating-point.
-
As one of valid boolean constants
-
As a Tcl variable, using standard $ notation. The variable’s value will be used as the operand.
-
As a string enclosed in double-quotes. The expression parser will perform backslash, variable, and command substitutions on the information between the quotes, and use the resulting value as the operand
-
As a string enclosed in braces. The characters between the open brace and matching close brace will be used as the operand without any substitutions.
-
As a Tcl command enclosed in brackets. The command will be executed and its result will be used as the operand.
Where substitutions occur above (e.g. inside quoted strings), they are performed by the expression processor. However, an additional layer of substitution may already have been performed by the command parser before the expression processor was called.
As discussed below, it is usually best to enclose expressions in braces to prevent the command parser from performing substitutions on the contents.
For some examples of simple expressions, suppose the variable a has the value 3 and the variable b has the value 6. Then the expression on the left side of each of the lines below will evaluate to the value on the right side of the line:
$a + 3.1 6.1
2 + "$a.$b" 5.6
4*[llength "6 2"] 8
{word one} < "word $a" 0The valid operators are listed below, grouped in decreasing order of precedence:
-
int() double() round() abs(), rand(), srand() -
Unary functions (except rand() which takes no arguments)
-
int()converts the numeric argument to an integer by truncating down. -
double()converts the numeric argument to floating point. -
round()converts the numeric argument to the closest integer value. -
abs()takes the absolute value of the numeric argument. -
rand()returns a pseudo-random floating-point value in the range (0,1). -
srand()takes an integer argument to (re)seed the random number generator. Returns the first random number from that seed.
-
-
sin() cos() tan() asin() acos() atan() sinh() cosh() tanh() ceil() floor() exp() log() log10() sqrt() -
Unary math functions. If Jim is compiled with math support, these functions are available.
-
- + ~ ! -
Unary minus, unary plus, bit-wise NOT, logical NOT. None of these operands may be applied to string operands, and bit-wise NOT may be applied only to integers.
-
** pow(x,y) -
Power. e.g. xy. If Jim is compiled with math support, supports doubles and integers. Otherwise supports integers only. (Note that the math-function form has the same highest precedence)
-
* / % -
Multiply, divide, remainder. None of these operands may be applied to string operands, and remainder may be applied only to integers.
-
+ - -
Add and subtract. Valid for any numeric operands.
-
<< >> <<< >>> -
Left and right shift, left and right rotate. Valid for integer operands only.
-
NOTE The rotate operations are specific to Jim Tcl and operate on unsigned 32 bit integers, even if the native word size is 64 bits.
-
< > <= >= -
Boolean less, greater, less than or equal, and greater than or equal. Each operator produces 1 if the condition is true, 0 otherwise. These operators may be applied to strings as well as numeric operands, in which case string comparison is used.
-
lt gt le ge -
Boolean less, greater, less than or equal, and greater than or equal. Each operator produces 1 if the condition is true, 0 otherwise. These operators differ from the above in that they use string comparison for all operands, including numeric.
-
== != -
Boolean equal and not equal. Each operator produces a zero/one result. Valid for all operand types. Note that values will be converted to integers if possible, then floating point types, and finally strings will be compared. It is recommended that eq and ne should be used for string comparison.
-
eq ne -
String equal and not equal. Uses the string value directly without attempting to convert to a number first.
-
=* -
String glob match. The left and side is the string to match and the right and side is the pattern. See STRING MATCHING.
-
=~ -
String regexp match. The left and side is the string to match and the right and side is the regular expression. See REGULAR EXPRESSIONS.
-
in ni -
String in list and not in list. For in, result is 1 if the left operand (as a string) is contained in the right operand (as a list), or 0 otherwise. The result for
{$a ni $list}is equivalent to{!($a in $list)}. -
& -
Bit-wise AND. Valid for integer operands only.
-
| -
Bit-wise OR. Valid for integer operands only.
-
^ -
Bit-wise exclusive OR. Valid for integer operands only.
-
&& -
Logical AND. Produces a 1 result if both operands are non-zero, 0 otherwise. Valid for numeric operands only (integers or floating-point).
-
|| -
Logical OR. Produces a 0 result if both operands are zero, 1 otherwise. Valid for numeric operands only (integers or floating-point).
-
x ? y : z -
If-then-else, as in C. If
xevaluates to non-zero, then the result is the value ofy. Otherwise the result is the value ofz. Thexoperand must have a numeric value, whileyandzcan be of any type.
See the C manual for more details on the results produced by each operator. All of the binary operators group left-to-right within the same precedence level. For example, the expression
4*2 < 7evaluates to 0.
The &&, ||, and ?: operators have lazy evaluation, just as
in C, which means that operands are not evaluated if they are not
needed to determine the outcome. For example, in
$v ? [a] : [b]only one of [a] or [b] will actually be evaluated,
depending on the value of $v.
All internal computations involving integers are done with the C type long long if available, or long otherwise, and all internal computations involving floating-point are done with the C type double.
When converting a string to floating-point, exponent overflow is detected and results in a Tcl error. For conversion to integer from string, detection of overflow depends on the behaviour of some routines in the local C library, so it should be regarded as unreliable. In any case, overflow and underflow are generally not detected reliably for intermediate results.
Conversion among internal representations for integer, floating-point, string operands is done automatically as needed. For arithmetic computations, integers are used until some floating-point number is introduced, after which floating-point is used. For example,
5 / 4yields the result 1, while
5 / 4.0
5 / ( [string length "abcd"] + 0.0 )both yield the result 1.25.
String values may be used as operands of the comparison operators, although the expression evaluator tries to do comparisons as integer or floating-point when it can. If one of the operands of a comparison is a string and the other has a numeric value, the numeric operand is converted back to a string using the C sprintf format specifier %d for integers and %g for floating-point values. For example, the expressions
"0x03" > "2"
"0y" < "0x12"both evaluate to 1. The first comparison is done using integer comparison, and the second is done using string comparison after the second operand is converted to the string 18.
In general it is safest to enclose an expression in braces when entering it in a command: otherwise, if the expression contains any white space then the Tcl interpreter will split it among several arguments. For example, the command
expr $a + $bresults in three arguments being passed to expr: $a,
+, and $b. In addition, if the expression isn’t in braces
then the Tcl interpreter will perform variable and command substitution
immediately (it will happen in the command parser rather than in
the expression parser). In many cases the expression is being
passed to a command that will evaluate the expression later (or
even many times if, for example, the expression is to be used to
decide when to exit a loop). Usually the desired goal is to re-do
the variable or command substitutions each time the expression is
evaluated, rather than once and for all at the beginning. For example,
the command
for {set i 1} $i<=10 {incr i} {...} ** WRONG **is probably intended to iterate over all values of i from 1 to 10.
After each iteration of the body of the loop, for will pass
its second argument to the expression evaluator to see whether or not
to continue processing. Unfortunately, in this case the value of i
in the second argument will be substituted once and for all when the
for command is parsed. If i was 0 before the for
command was invoked then the second argument of for will be 0<=10
which will always evaluate to 1, even though i eventually
becomes greater than 10. In the above case the loop will never
terminate. Instead, the expression should be placed in braces:
for {set i 1} {$i<=10} {incr i} {...} ** RIGHT **This causes the substitution of i to be delayed; it will be re-done each time the expression is evaluated, which is the desired result.
LISTS
The third major way that strings are interpreted in Tcl is as lists. A list is just a string with a list-like structure consisting of fields separated by white space. For example, the string
Al Sue Anne Johnis a list with four elements or fields. Lists have the same basic structure as command strings, except that a newline character in a list is treated as a field separator just like space or tab. Conventions for braces and quotes and backslashes are the same for lists as for commands. For example, the string
a b\ c {d e {f g h}}is a list with three elements: a, b c, and d e {f g h}.
Whenever an element is extracted from a list, the same rules about braces and quotes and backslashes are applied as for commands. Thus in the example above when the third element is extracted from the list, the result is
d e {f g h}(when the field was extracted, all that happened was to strip off the outermost layer of braces). Command substitution and variable substitution are never made on a list (at least, not by the list-processing commands; the list can always be passed to the Tcl interpreter for evaluation).
LIST EXPANSION
A new addition to Tcl 8.5 is the ability to expand a list into separate arguments. Support for this feature is also available in Jim.
Consider the following attempt to exec a list:
set cmd {ls -l}
exec $cmdThis will attempt to exec a command named "ls -l", which will clearly not
work. Typically eval and concat are required to solve this problem, however
it can be solved much more easily with \{*}.
exec {*}$cmdThis will expand the following argument into individual elements and then evaluate the resulting command.
Note that the official Tcl syntax is \{*}, however {expand} is retained
for backward compatibility with experimental versions of this feature.
REGULAR EXPRESSIONS
Jim Tcl provides two commands that support string matching using regular
expressions, regexp and regsub, as well as switch -regexp and
lsearch -regexp.
Regular expressions may be implemented one of two ways. Either using the system’s C library POSIX regular expression support, or using the built-in regular expression engine. The differences between these are described below.
NOTE Tcl 7.x and 8.x use perl-style Advanced Regular Expressions (ARE).
POSIX Regular Expressions
If the system supports POSIX regular expressions, and UTF-8 support is not enabled,
this support will be used by default. The type of regular expressions supported are
Extended Regular Expressions (ERE) rather than Basic Regular Expressions (BRE).
See REG_EXTENDED in the documentation.
Using the system-supported POSIX regular expressions will typically
make for the smallest code size, but some features such as UTF-8
and \w, \d, \s are not supported, and null characters
in strings are not supported.
See regex(3) and regex(7) for full details.
Jim built-in Regular Expressions
The Jim built-in regular expression engine may be selected with ./configure --with-jim-regexp
or it will be selected automatically if UTF-8 support is enabled.
This engine supports UTF-8 as well as some ARE features. The differences with both Tcl 7.x/8.x
and POSIX are highlighted below.
-
UTF-8 strings and patterns are both supported
-
All Tcl character classes are supported (e.g.
[:alnum:],[:digit:],[:space:]), but… -
Character classes apply to ASCII characters only
-
Supported shorthand character classes:
\w=[:alnum:],\W=^[:alnum:],\d=[:digit:],\D=^[:digit:],\s=[:space:], +\S=^[:space:] -
Supported constraint escapes:
\m=\<= start of word,\M=\>= end of word,\A= start of string,\Z= end of string -
Backslash escapes may be used within regular expressions, such as
\n= newline,\uNNNN= unicode -
Support for the
?non-greedy quantifier. e.g.*? -
Support for non-capturing parentheses
(?:…) -
Jim Tcl considers that both patterns and strings end at a null character (
\x00) -
Jim Tcl does not support back references. e.g.
\1
STRING MATCHING
A number of commands in Jim support C-shell style "glob matching", including
string match, switch -glob, array names and others. This form of string matching
works as follows:
A test occurs where a string is matched against a pattern. The match is considered
successful if the contents of string and pattern are identical except that the
following special sequences may appear in pattern:
-
* -
Matches any sequence of characters in
string, including an empty string. -
? -
Matches any single character in
string. -
[chars] -
Matches any character in the set given by
chars. If a sequence of the formx-yappears inchars, then any character betweenxandy, inclusive, will match. -
\x -
Matches the single character
x. This provides a way of avoiding the special interpretation of the characters\*?[]inpattern.
COMMAND RESULTS
Each command produces two results: a code and a string. The code indicates whether the command completed successfully or not, and the string gives additional information. The valid codes are defined in jim.h, and are:
-
JIM_OK(0) -
This is the normal return code, and indicates that the command completed successfully. The string gives the command’s return value.
-
JIM_ERR(1) -
Indicates that an error occurred; the string gives a message describing the error.
-
JIM_RETURN(2) -
Indicates that the
returncommand has been invoked, and that the current procedure (or top-level command orsourcecommand) should return immediately. The string gives the return value for the procedure or command. -
JIM_BREAK(3) -
Indicates that the
breakcommand has been invoked, so the innermost loop should abort immediately. The string should always be empty. -
JIM_CONTINUE(4) -
Indicates that the
continuecommand has been invoked, so the innermost loop should go on to the next iteration. The string should always be empty. -
JIM_SIGNAL(5) -
Indicates that a signal was caught while executing a commands. The string contains the name of the signal caught. See the
signalandcatchcommands. -
JIM_EXIT(6) -
Indicates that the command called the
exitcommand. The string contains the exit code. -
JIM_USAGE(-1) -
This is a special return code that is automatically translated into JIM_ERR with the command usage (from Jim_RegisterCommand()) as the message.
Tcl programmers do not normally need to think about return codes,
since JIM_OK is almost always returned. If anything else is returned
by a command, then the Tcl interpreter immediately stops processing
commands and returns to its caller. If there are several nested
invocations of the Tcl interpreter in progress, then each nested
command will usually return the error to its caller, until eventually
the error is reported to the top-level application code. The
application will then display the error message for the user.
In a few cases, some commands will handle certain error conditions
themselves and not return them upwards. For example, the for
command checks for the JIM_BREAK code; if it occurs, then for
stops executing the body of the loop and returns JIM_OK to its
caller. The for command also handles JIM_CONTINUE codes and the
procedure interpreter handles JIM_RETURN codes. The catch
command allows Tcl programs to catch errors and handle them without
aborting command interpretation any further.
The info returncodes command may be used to programmatically map between
return codes and names.
PROCEDURES
Tcl allows you to extend the command interface by defining procedures. A Tcl procedure can be invoked just like any other Tcl command (it has a name and it receives one or more arguments). The only difference is that its body isn’t a piece of C code linked into the program; it is a string containing one or more other Tcl commands.
The proc command is used to create a new Tcl command procedure:
proc name arglist ?statics? body
The new command is named name, and it replaces any existing command
there may have been by that name. Whenever the new command is
invoked, the contents of body will be executed by the Tcl
interpreter.
arglist specifies the formal arguments to the procedure.
It consists of a list, possibly empty, of the following
argument specifiers:
-
name -
Required Argument - A simple argument name.
-
{name default} -
Optional Argument - A two-element list consisting of the argument name, followed by the default value, which will be used if the corresponding argument is not supplied.
-
&name -
Reference Argument - The caller is expected to pass the name of an existing variable. An implicit
upvar1 origname name -
args -
Variable Argument - The special name
args, which is assigned all remaining arguments (including none) as a list. The variable argument may only be specified once. Note that the syntax{args newname}may be used to retain the special behaviour ofargswith a different local name. In this case, the variable is namednewnamerather thanargs.
When the command is invoked, a local variable will be created for each of the formal arguments to the procedure; its value will be the value of corresponding argument in the invoking command or the argument’s default value.
Arguments with default values need not be specified in a procedure invocation. However, there must be enough actual arguments for all required arguments, and there must not be any extra actual arguments (unless the Variable Argument is specified).
Actual arguments are assigned to formal arguments as in left-to-right order with the following precedence.
-
Required Arguments (including Reference Arguments)
-
Optional Arguments
-
Variable Argument
The following example illustrates precedence. Assume a procedure declaration:
proc p {{a A} args b {c C} d} {...}This procedure requires at least two arguments, but can accept an unlimited number.
The following table shows how various numbers of arguments are assigned.
Values marked as - are assigned the default value.
| Number of arguments | a | args | b | c | d |
|---|---|---|---|---|---|
2 |
- |
- |
1 |
- |
2 |
3 |
1 |
- |
2 |
- |
3 |
4 |
1 |
- |
2 |
3 |
4 |
5 |
1 |
2 |
3 |
4 |
5 |
6 |
1 |
2,3 |
4 |
5 |
6 |
When body is being executed, variable names normally refer to local
variables, which are created automatically when referenced and deleted
when the procedure returns. One local variable is automatically created
for each of the procedure’s arguments. Global variables can be
accessed by invoking the global command or via the :: prefix.
New in Jim
In addition to procedure arguments, Jim procedures may declare static variables. These variables scoped to the procedure and initialised at procedure definition. Either from the static variable definition, or from the enclosing scope.
Consider the following example:
. set a 1
. proc a {} {a {b 2}} {
set c 1
puts "$a $b $c"
incr a
incr b
incr c
}
. a
1 2 1
. a
2 3 1The static variable a has no initialiser, so it is initialised from
the enclosing scope with the value 1. (Note that it is an error if there
is no variable with the same name in the enclosing scope). However b
has an initialiser, so it is initialised to 2.
Unlike a local variable, the value of a static variable is retained across invocations of the procedure.
In addition to static variables by value, static variables may also be defined by "reference" by using a leading "&" character. In this case, the statics point to the original variable and when one changes, they both change. For example, here a changes changes the value of the original x.
. set x 1
. proc a {} {&x} {
incr x
}
. a
2
. a
3
. puts $x
3See the proc command for information on how to define procedures
and what happens when they are invoked. See also NAMESPACES.
VARIABLES - SCALARS AND ARRAYS
Tcl allows the definition of variables and the use of their values
either through $-style variable substitution, the set
command, or a few other mechanisms.
Variables need not be declared: a new variable will automatically be created each time a new variable name is used.
Tcl supports two types of variables: scalars and arrays. A scalar variable has a single value, whereas an array variable can have any number of elements, each with a name (called its index) and a value.
Array indexes may be arbitrary strings; they need not be numeric. Parentheses are used refer to array elements in Tcl commands. For example, the command
set x(first) 44will modify the element of x whose index is first so that its new value is 44.
Two-dimensional arrays can be simulated in Tcl by using indexes that contain multiple concatenated values. For example, the commands
set a(2,3) 1
set a(3,6) 2set the elements of a whose indexes are 2,3 and 3,6.
In general, array elements may be used anywhere in Tcl that scalar variables may be used.
If an array is defined with a particular name, then there may not be a scalar variable with the same name.
Similarly, if there is a scalar variable with a particular name then it is not possible to make array references to the variable.
To convert a scalar variable to an array or vice versa, remove
the existing variable with the unset command.
The array command provides several features for dealing
with arrays, such as querying the names of all the elements of
the array and converting between an array and a list.
Variables may be either global or local. If a variable
name is used when a procedure isn’t being executed, then it
automatically refers to a global variable. Variable names used
within a procedure normally refer to local variables associated with that
invocation of the procedure. Local variables are deleted whenever
a procedure exits. Either global command may be used to request
that a name refer to a global variable for the duration of the current
procedure (this is somewhat analogous to extern in C), or the variable
may be explicitly scoped with the :: prefix. For example
. set a 1
. set b 2
. proc p {} {
set c 3
global a
puts "$a $::b $c"
}
. pwill output:
1 2 3ARRAYS AS LISTS IN JIM
Unlike Tcl, Jim can automatically convert between a list (with an even number of elements) and an array value. This is similar to the way Tcl can convert between a string and a list.
For example:
set a {1 one 2 two}
puts $a(2)will output:
twoThe reverse is also true where an array will be converted into a list.
set a(1) one; set a(2) two
puts $awill output:
1 one 2 twoDICTIONARY VALUES
Tcl 8.5 introduced the dict command, and Jim Tcl has added a version of this command. Dictionaries provide efficient access to key-value pairs, just like arrays, but dictionaries are pure values. This means that you can pass them to a procedure just as a list or a string. Tcl dictionaries are therefore much more like Tcl lists, except that they represent a mapping from keys to values, rather than an ordered sequence.
You can nest dictionaries, so that the value for a particular key consists of another dictionary. That way you can elegantly build complicated data structures, such as hierarchical databases. You can also combine dictionaries with other Tcl data structures. For instance, you can build a list of dictionaries that themselves contain lists.
Dictionaries are values that contain an efficient, order-preserving mapping from arbitrary keys to arbitrary values. Each key in the dictionary maps to a single value. They have a textual format that is exactly that of any list with an even number of elements, with each mapping in the dictionary being represented as two items in the list. When a command takes a dictionary and produces a new dictionary based on it (either returning it or writing it back into the variable that the starting dictionary was read from) the new dictionary will have the same order of keys, modulo any deleted keys and with new keys added on to the end. When a string is interpreted as a dictionary and it would otherwise have duplicate keys, only the last value for a particular key is used; the others are ignored, meaning that, "apple banana" and "apple carrot apple banana" are equivalent dictionaries (with different string representations).
Note that in Jim, arrays are implemented as dictionaries. Thus automatic conversion between lists and dictionaries applies as it does for arrays.
. dict set a 1 one
1 one
. dict set a 2 two
1 one 2 two
. puts $a
1 one 2 two
. puts $a(2)
two
. dict set a 3 T three
1 one 2 two 3 {T three}See the dict command for more details.
NAMESPACES
Tcl added namespaces as a mechanism avoiding name clashes, especially in applications including a number of 3rd party components. While there is less need for namespaces in Jim Tcl (which does not strive to support large applications), it is convenient to provide a subset of the support for namespaces to easy porting code from Tcl.
Jim Tcl currently supports "light-weight" namespaces which should be adequate for most
purposes. This feature is currently experimental. See README.namespaces for more information
and the documentation of the namespace command.
GARBAGE COLLECTION, REFERENCES, LAMBDA FUNCTION
Unlike Tcl, Jim has some sophisticated support for functional programming. These are described briefly below.
More information may be found at http://wiki.tcl.tk/13847
References
A reference can be thought of as holding a value with one level of indirection, where the value may be garbage collected when unreferenced. Consider the following example:
. set r [ref "One String" test]
<reference.<test___>.00000000000000000000>
. getref $r
One StringThe operation ref creates a references to the value specified by the
first argument. (The second argument is a "type" used for documentation purposes).
The operation getref is the dereferencing operation which retrieves the value
stored in the reference.
. setref $r "New String"
New String
. getref $r
New StringThe operation setref replaces the value stored by the reference. If the old value
is no longer accessible by any reference, it will eventually be automatically be garbage
collected.
Garbage Collection
Normally, all values in Tcl are passed by value. As such values are copied and released automatically as necessary.
With the introduction of references, it is possible to create values whose lifetime transcend their scope. To support this, case, the Jim system will periodically identify and discard objects which are no longer accessible by any reference.
The collect command may be used to force garbage collection. Consider a reference created
with a finalizer:
. proc f {ref value} { puts "Finaliser called for $ref,$value" }
. set r [ref "One String" test f]
<reference.<test___>.00000000000
. collect
0
. set r ""
. collect
Finaliser called for <reference.<test___>.00000000000,One String
1Note that once the reference, r, was modified so that it no longer contained a reference to the value, the garbage collector discarded the value (after calling the finalizer).
The finalizer for a reference may be examined or changed with the finalize command
. finalize $r
f
. finalize $r newf
newfLambda Function
Jim provides a garbage collected lambda function. This is a procedure
which is able to create an anonymous procedure. Consider:
. set f [lambda {a} {{x 0}} { incr x $a }]
. $f 1
1
. $f 2
3
. set f ""This create an anonymous procedure (with the name stored in f), with a static variable which is incremented by the supplied value and the result returned.
Once the procedure name is no longer accessible, it will automatically be deleted when the garbage collector runs.
The procedure may also be delete immediately by renaming it "". e.g.
. rename $f ""UTF-8 AND UNICODE
If Jim is built with UTF-8 support enabled (configure --enable-utf),
then most string-related commands become UTF-8 aware. These include,
but are not limited to, string match, split, glob, scan and
format.
UTF-8 encoding has many advantages, but one of the complications is that
characters can take a variable number of bytes. Thus the addition of
string bytelength which returns the number of bytes in a string,
while string length returns the number of characters.
If UTF-8 support is not enabled, all commands treat bytes as characters
and string bytelength returns the same value as string length.
Note that even if UTF-8 support is not enabled, the \uNNNN and related syntax
is still available to embed UTF-8 sequences.
Jim Tcl supports all currently defined unicode codepoints. That is 21 bits, up to +U+1FFFFF.
String Matching
Commands such as string match, lsearch -glob, array names and others use
STRING MATCHING rules. These commands support UTF-8. For example:
string match a\[\ua0-\ubf\]b "a\u00a3b"format and scan
format %c allows a unicode codepoint to be be encoded. For example, the following will return
a string with two bytes and one character. The same as \ub5
format %c 0xb5format respects widths as character widths, not byte widths. For example, the following will
return a string with three characters, not three bytes.
format %.3s \ub5\ub6\ub7\ub8Similarly, scan … %c allows a UTF-8 to be decoded to a unicode codepoint. The following will set
a to 181 (0xb5) and b to 65 (0x41).
scan \u00b5A %c%c a bscan %s will also accept a character class, including unicode ranges.
String Classes
string is has not been extended to classify UTF-8 characters. Therefore, the following
will return 0, even though the string may be considered to be alphabetic.
string is alpha \ub5TestThis does not affect the string classes ascii, control, digit, double, integer or xdigit.
Case Mapping and Conversion
Jim provides a simplified unicode case mapping. This means that case conversion and comparison will not increase or decrease the number of characters in a string. (Although it may change the number of bytes).
Invalid UTF-8 Sequences
Some UTF-8 character sequences are invalid, such as those beginning with 0xff, those which represent character sequences longer than 3 bytes (greater than U+FFFF), and those which end prematurely, such as a lone 0xc2.
In these situations, the offending bytes are treated as single characters. For example, the following returns 2.
string bytelength \xff\xffRegular Expressions
If UTF-8 support is enabled, the built-in regular expression engine will be selected which supports UTF-8 strings and patterns.
BUILT-IN COMMANDS
The Tcl library provides the following built-in commands, which will be available in any application using Tcl. In addition to these built-in commands, there may be additional commands defined by each application, plus commands defined as Tcl procedures.
In the command syntax descriptions below, words in boldface are
literals that you type verbatim to Tcl.
Words in italics are meta-symbols; they serve as names for any of
a range of values that you can type.
Optional arguments or groups of arguments are indicated by enclosing them
in ?question-marks?.
Ellipses (...) indicate that any number of additional
arguments or groups of arguments may appear, in the same format
as the preceding argument(s).
Command Index
alarm
alarm seconds
Delivers the SIGALRM signal to the process after the given
number of seconds. If the platform supports ualarm(3) then
the argument may be a floating point value. Otherwise it must
be an integer.
Note that unless a signal handler for SIGALRM has been installed
(see signal), the process will exit on this signal.
alias
alias name args...
Creates a single word alias (command) for one or more words. For example,
the following creates an alias for the command info exists.
alias e info exists
if {[e var]} {
...
}append
append varName value ?value value …?
Append all of the value arguments to the current value
of variable varName. If varName doesn’t exist,
it is given a value equal to the concatenation of all the
value arguments.
apply
apply lambdaExpr ?arg1 arg2 ...?
array
array option arrayName ?arg...?
This command performs one of several operations on the
variable given by arrayName.
Note that in general, if the named array does not exist, the array command behaves
as though the array exists but is empty.
The option argument determines what action is carried out by the
command. The legal options (which may be abbreviated) are:
-
array exists arrayName -
Returns 1 if
arrayNameis an array variable, 0 if there is no variable by that name. -
array get arrayName ?pattern? -
Returns a list containing pairs of elements. The first element in each pair is the name of an element in
arrayNameand the second element of each pair is the value of the array element. The order of the pairs is undefined. Ifpatternis not specified, then all of the elements of the array are included in the result. Ifpatternis specified, then only those elements whose names matchpattern(using STRING MATCHING rules) are included. IfarrayNameisn’t the name of an array variable, or if the array contains no elements, then an empty list is returned. -
array names arrayName ?pattern? -
Returns a list containing the names of all of the elements in the array that match
pattern. Ifpatternis omitted then the command returns all of the element names in the array. Ifpatternis specified, then only those elements whose names matchpattern(using STRING MATCHING rules) are included. If there are no (matching) elements in the array, or ifarrayNameisn’t the name of an array variable, then an empty string is returned. -
array set arrayName list -
Sets the values of one or more elements in
arrayName.listmust have a form like that returned by array get, consisting of an even number of elements. Each odd-numbered element in list is treated as an element name within arrayName, and the following element in list is used as a new value for that array element. If the variablearrayNamedoes not already exist and list is empty,arrayNameis created with an empty array value. -
array size arrayName -
Returns the number of elements in the array. If
arrayNameisn’t the name of an array then 0 is returned. -
array unset arrayName ?pattern? -
Unsets all of the elements in the array that match
pattern(using STRING MATCHING rules). IfarrayNameisn’t the name of an array variable or there are no matching elements in the array, no error will be raised. Ifpatternis omitted andarrayNameis an array variable, then the command unsets the entire array. The command always returns an empty string.
break
break ?n?
This command may be invoked only inside the body of a loop command
such as for, foreach, while or loop. It returns a JIM_BREAK code
to signal the innermost containing loop command to return immediately.
If n is given it breaks out of that many loops. break 1 is equivalent
to a simple break while in the following example, break will exit both
loops.
loop i 5 {
loop j 6 {
if {$i == 3 && $j == 2} {
break 2
}
}
}case
The obsolete case command has been removed from Jim Tcl since v0.75.
Use switch instead.
catch
catch ?-?no?code ...? ?--? command ?resultVarName? ?optionsVarName?
The catch command may be used to prevent errors from aborting
command interpretation. catch evaluates command, and returns a
JIM_OK code, regardless of any errors that might occur while
executing command (with the possible exception of JIM_SIGNAL -
see below).
The return value from catch is a decimal string giving the code
returned by the Tcl interpreter after executing command. This
will be 0 (JIM_OK) if there were no errors in command; otherwise
it will have a non-zero value corresponding to one of the exceptional
return codes (see jim.h for the definitions of code values, or the
info returncodes command).
If the resultVarName argument is given, then it gives the name
of a variable; catch will set the value of the variable to the
string returned from command (either a result or an error message).
If the optionsVarName argument is given, then it gives the name
of a variable; catch will set the value of the variable to a
dictionary. For any return code other than JIM_RETURN, the value
for the key -code will be set to the return code. For JIM_RETURN
it will be set to the code given in return -code. Additionally,
for the return code JIM_ERR, the value of the key -errorinfo
will contain the current stack trace (the same result as info stacktrace),
the value of the key -errorcode will contain the
same value as the global variable $::errorCode, and the value of
the key -level will be the current return level (see return -level).
This can be useful to rethrow an error:
if {[catch {...} msg opts]} {
...maybe do something with the error...
incr opts(-level)
return {*}$opts $msg
}Normally catch will not catch any of the codes JIM_EXIT, JIM_EVAL or JIM_SIGNAL.
The set of codes which will be caught may be modified by specifying the one more codes before
command.
e.g. To catch JIM_EXIT but not JIM_BREAK or JIM_CONTINUE
catch -exit -nobreak -nocontinue -- { ... }The use of -- is optional. It signifies that no more return code options follow.
cd
cd dirName
Change the current working directory to dirName.
Returns an empty string.
This command can potentially be disruptive to an application, so it may be removed in some applications.
clock
-
clock seconds -
Returns the current time as seconds since the epoch.
-
clock clicks -
Returns the current time in "clicks", a system-dependent, high-resolution time.
-
clock microseconds -
Returns the current time in microseconds.
-
clock milliseconds -
Returns the current time in milliseconds.
-
clock format seconds ?-format format? ?-gmt boolean? -
Format the given time (seconds since the epoch) according to the given format. See strftime(3) for supported formats. If no format is supplied, "%c" is used.
-
If
booleanis true, processing is performed in UTC. Ifbooleanis false (the default), processing is performed in the local time zone. -
clock scan str -format format ?-gmt boolean? -
Scan the given time string using the given format string. See strptime(3) for supported formats. See
clockformatfor the handling of -gmt.
NOTE Some systems such as 32-bit Linux have only a 32-bit time_t, and are therefore not year 2038 compliant.
collect
collect
Normally reference garbage collection is automatically performed periodically.
However it may be run immediately with the collect command.
See GARBAGE COLLECTION for more detail.
concat
concat arg ?arg ...?
This command treats each argument as a list and concatenates them into a single list. It permits any number of arguments. For example, the command
concat a b {c d e} {f {g h}}will return
a b c d e f {g h}as its result.
continue
continue ?n?
This command may be invoked only inside the body of a loop command such
as for, foreach, while or loop. It returns a JIM_CONTINUE code to
signal the innermost containing loop command to skip the remainder of
the loop’s body but continue with the next iteration of the loop.
If n is given it breaks out of n-1 loops and then continues the nth loop.
continue 1 is equivalent to a simple continue. (See also break).
curry
curry args...
Similar to alias except it creates an anonymous procedure (lambda) instead of
a named procedure.
The following creates a local, unnamed alias for the command info exists.
set e [local curry info exists]
if {[$e var]} {
...
}curry returns the name of the procedure.
defer
defer script
This command is a simple helper command to add a script to the $jim::defer variable
that will run when the current proc or interpreter exits. For example:
. proc a {} { defer {puts "Leaving a"}; puts "Exit" }
. a
Exit
Leaving aIf the $jim::defer variable exists, it is treated as a list of scripts to run
when the proc or interpreter exits.
dict
dict option ?arg...?
Performs one of several operations on dictionary values.
The option argument determines what action is carried out by the
command. The legal options are:
-
dict append dictionaryName key ?string …? -
This appends the given string (or strings) to the value that the given key maps to in
dictionaryName. Non-existent keys are treated as if they map to an empty string. -
dict create ?key value ...? -
Create and return a new dictionary value that contains each of the key/value mappings listed as arguments (keys and values alternating, with each key being followed by its associated value.)
-
dict exists dictionary key ?key ...? -
Returns a boolean value indicating whether the given key (or path of keys through a set of nested dictionaries) exists in the given dictionary value. This returns a true value exactly when
dictgeton that path will succeed. -
dict for {keyvar valuevar} dictionary script -
TBD
-
dict get dictionary ?key ...? -
Given a dictionary value (first argument) and a key (second argument), this will retrieve the value for that key. Where several keys are supplied, the behaviour of the command shall be as if the result of "
dictget $dictVal $key" was passed as the first argument to dict get with the remaining arguments as second (and possibly subsequent) arguments. This facilitates lookups in nested dictionaries. If no keys are provided, dict would return a list containing pairs of elements in a manner similar to array get. That is, the first element of each pair would be the key and the second element would be the value for that key. It is an error to attempt to retrieve a value for a key that is not present in the dictionary. -
dict getdef dictionary ?key ...? key default -
Alias for
dictgetwithdefault. -
dict getwithdefault dictionary ?key ...? key default -
Similar to
dictgetexcept if no value exists in the dictionary for the give key(s), returnsdefaultinstead. -
dict incr dictionaryName key ?increment? -
This adds the given increment value (an integer that defaults to 1 if not specified) to the value that the given key maps to in
dictionaryName. Non-existent keys are treated as if they map to 0. It is an error to increment a value for an existing key if that value is not an integer. -
dict info dictionary -
Returns some information about the utilisation of the data within the hashtable that represents
dictionary. -
dict keys dictionary ?pattern? -
Returns a list of the keys in the dictionary. If
patternis specified, then only those keys whose names matchpattern(using STRING MATCHING rules) are included. -
dict lappend dictionaryName key ?value …? -
This appends the given items to the list value that the given key maps to in
dictionaryName. Non-existent keys are treated as if they map to the empty list. -
dict merge ?dictionary ...? -
Return a dictionary that contains the contents of each of the
dictionaryarguments. Where two (or more) dictionaries contain a mapping for the same key, the resulting dictionary maps that key to the value according to the last dictionary on the command line containing a mapping for that key. -
dict replace dictionary ?key value …? -
Return a new dictionary that is a copy of
dictionaryexcept with some values different or some extra key/value pairs added. It is legal for this command to be called with no key/value pairs, but illegal for this command to be called with a key but no value. -
dict set dictionaryName key ?key ...? value -
This operation takes the
nameof a variable containing a dictionary value and places an updated dictionary value in that variable containing a mapping from the given key to the given value. When multiple keys are present, this operation creates or updates a chain of nested dictionaries. -
dict size dictionary -
Return the number of key/value mappings in the given dictionary value.
-
dict unset dictionaryName key ?key ...? value -
This operation (the companion to
dictset) takes the name of a variable containing a dictionary value and places an updated dictionary value in that variable that does not contain a mapping for the given key. Where multiple keys are present, this describes a path through nested dictionaries to the mapping to remove. At least one key must be specified, but the last key on the key-path need not exist. All other components on the path must exist. -
dict update dictionaryName key varName ?key VarName …? script -
TBD
-
dict values dictionary ?globPattern? -
Return a list of all values in
dictionary. If a pattern is supplied, only those values that match it (according to the rules ofstringmatch) will be returned. The returned values will be in the order of that the keys associated with those values were inserted into the dictionary. -
dict with dictionaryName key ?key ...? script -
Execute the Tcl script in
scriptwith the value for each key indictionaryNamemapped to a variable with the same name. Where one or more keys are given, these indicate a chain of nested dictionaries, with the innermost dictionary being the one opened out for the execution of body. MakingdictionaryNameunreadable will make the updates to the dictionary be discarded, and this also happens if the contents ofdictionaryNameare adjusted so that the chain of dictionaries no longer exists. The result ofdictwithis (unless some kind of error occurs) the result of the evaluation of body. -
The variables are mapped in the scope enclosing the
dictwith; it is recommended that this command only be used in a local scope (procedure). Because of this, the variables set bydictwithwill continue to exist after the command finishes (unless explicitly unset). Note that changes to the contents ofdictionaryNameonly happen whenscriptterminates.
ensemble
ensemble name ?-automap? prefix
Create a single ensemble command that redirects to individual commands based on the prefix.
By default, the prefix is name followed by a single space.
For example, consider:
proc {test open} {name} { ... }
proc {test close} {handle} { ... }
proc {test show} {handle} { ... }
ensemble testNow the test command has been created that redirects based on the first argument.
e.g. test open $filename ⇒ {test open} $filename
env
env ?name? ?default?
If name is supplied, returns the value of name from the initial
environment (see getenv(3)). An error is returned if name does not
exist in the environment, unless default is supplied - in which case
that value is returned instead.
If no arguments are supplied, returns a list of all environment variables
and their values as {name value ...}
See also the global variable ::env
error
error message ?stacktrace?
Returns a JIM_ERR code, which causes command interpretation to be
unwound. message is a string that is returned to the application
to indicate what went wrong.
If the stacktrace argument is provided and is non-empty,
it is used to initialize the stacktrace.
This feature is most useful in conjunction with the catch command:
if a caught error cannot be handled successfully, stacktrace can be used
to return a stack trace reflecting the original point of occurrence
of the error:
catch {...} errMsg
...
error $errMsg [info stacktrace]errorInfo
errorInfo error ?stacktrace?
Returns a human-readable representation of the given error message and stack trace. Typical usage is:
if {[catch {...} error]} {
puts stderr [errorInfo $error [info stacktrace]]
exit 1
}See also error.
eval
eval arg ?arg...?
eval takes one or more arguments, which together comprise a Tcl
command (or collection of Tcl commands separated by newlines in the
usual way). eval concatenates all its arguments in the same
fashion as the concat command, passes the concatenated string to the
Tcl interpreter recursively, and returns the result of that
evaluation (or any error generated by it).
exec
exec arg ?arg...?
exec | {cmdlist ...} ?redirection ...?
This command treats its arguments as the specification
of one or more UNIX commands to execute as subprocesses.
The commands take the form of a standard shell pipeline;
| arguments separate commands in the
pipeline and cause standard output of the preceding command
to be piped into standard input of the next command (or |& for
both standard output and standard error).
Under normal conditions the result of the exec command
consists of the standard output produced by the last command
in the pipeline followed by the standard error output.
If any of the commands writes to its standard error file, then this will be included in the result after the standard output of the last command.
Note that unlike Tcl, data written to standard error does not cause
exec to return an error.
If any of the commands in the pipeline exit abnormally or
are killed or suspended, then exec will return an error.
If no standard error output was produced, or is redirected,
the error message will include the normal result, as above,
followed by error messages describing the abnormal terminations.
If any standard error output was produced, these abnormal termination messages are suppressed.
If the last character of the result or error message is a newline then that character is deleted from the result or error message for consistency with normal Tcl return values.
An arg (or redirection in the second form) may have one of the
following special forms:
-
>filename -
The standard output of the last command in the pipeline is redirected to the file. In this situation
execwill normally return an empty string. -
>>filename -
As above, but append to the file.
-
>@fileId -
The standard output of the last command in the pipeline is redirected to the given (writable) file descriptor (e.g. stdout, stderr, or the result of
open). In this situationexecwill normally return an empty string. -
2>filename -
The standard error of all commands in the pipeline is redirected to the file.
-
2>>filename -
As above, but append to the file.
-
2>@fileId -
The standard error of all commands in the pipeline is redirected to the given (writable) file descriptor.
-
2>@1 -
The standard error of all commands in the pipeline is redirected command output.
-
>&filename -
Both standard output from the last command and standard error from all commands in the pipeline are redirected to the file.
-
>>&filename -
As above, but append to the file.
-
<filename -
The standard input of the first command in the pipeline is taken from the file.
-
<<string -
The standard input of the first command is taken as the given immediate value.
-
<@fileId -
The standard input of the first command in the pipeline is taken from the given (readable) file descriptor.
Note that any of the forms that take an argument (filename, fileId or string)
their argument may be a separate word. e.g. << $str.
If there is no redirection of standard input, standard error or standard output, these are connected to the corresponding input or output of the application.
If the last arg or redirection is & then the command will be
executed in background. In this case the standard output from the last
command in the pipeline will go to the application’s standard output
unless redirected in the command, and error output from all the commands
in the pipeline will go to the application’s standard error file. The
return value of exec in this case is a list of process ids (pids) in
the pipeline.
Each arg becomes one word for a command, except for
|, <, <<, >, and & arguments, and the
arguments that follow <, <<, and >.
In the second form, cmdlist is the command list, so there
is no ambiguity about whether an argument or a redirection.
Note that this second form is not currently supported by Tcl.
The first word in each command is taken as the command name; the directories in the PATH environment variable are searched for an executable by the given name.
No glob expansion or other shell-like substitutions
are performed on the arguments to commands.
If the command fails, the global $::errorCode (and the -errorcode
option in catch) will be set to a list, as follows:
-
CHILDKILLED pid sigName msg -
This format is used when a child process has been killed because of a signal. The pid element will be the process’s identifier (in decimal). The sigName element will be the symbolic name of the signal that caused the process to terminate; it will be one of the names from the include file signal.h, such as SIGPIPE. The msg element will be a short human-readable message describing the signal, such as "write on pipe with no readers" for SIGPIPE.
-
CHILDSUSP pid sigName msg -
This format is used when a child process has been suspended because of a signal. The pid element will be the process’s identifier, in decimal. The sigName element will be the symbolic name of the signal that caused the process to suspend; this will be one of the names from the include file signal.h, such as SIGTTIN. The msg element will be a short human-readable message describing the signal, such as "background tty read" for SIGTTIN.
-
CHILDSTATUS pid code -
This format is used when a child process has exited with a non-zero exit status. The pid element will be the process’s identifier (in decimal) and the code element will be the exit code returned by the process (also in decimal).
The environment for the executed command is set from $::env (unless this variable is unset, in which case the original environment is used).
exists
exists ?-var|-proc|-command|-alias|-channel? name
Checks the existence of the given variable, procedure, command,
alias or channel respectively and returns 1 if it exists or 0 if not. This command
provides a more simplified/convenient version of info exists,
info procs, info commands, info aliases and info channels.
If the type is omitted, a type of -var is used. The type may be abbreviated.
exit
exit ?returnCode?
Terminate the process, returning returnCode to the
parent as the exit status.
If returnCode isn’t specified then it defaults
to 0.
Note that exit can be caught with catch.
expr
expr arg
Calls the expression processor to evaluate arg, and returns
the result as a string. See the section EXPRESSIONS above.
Note that Jim supports a shorthand syntax for expr as $(...)
The following two are identical.
set x [expr {3 * 2 + 1}]
set x $(3 * 2 + 1)However, note that the expr shorthand syntax may not be nested in an expression. This is to prevent the common mistake of writing:
if {$(1 + 2) == 3} {
...
}rather than:
if {(1 + 2) == 3} {
...
}file
file option name ?arg...?
Operate on a file or a file name. name is the name of a file.
option indicates what to do with the file name. Any unique
abbreviation for option is acceptable. The valid options are:
-
file atime name -
Return a decimal string giving the time at which file
namewas last accessed. The time is measured in the standard UNIX fashion as seconds from a fixed starting time (often January 1, 1970). If the file doesn’t exist or its access time cannot be queried then an error is generated. -
file copy ?-force? source target -
Copies file
sourceto filetarget. The source file must exist. The target file must not exist, unless-forceis specified. -
file delete ?-force? ?--? name... -
Deletes file or directory
name. If the file or directory doesn’t exist, nothing happens. If it can’t be deleted, an error is generated. Non-empty directories will not be deleted unless the-forceoptions is given. In this case no errors will be generated, even if the file/directory can’t be deleted. Use--if there is any possibility of the first name being-force. -
file dirname name -
Return all of the characters in
nameup to but not including the last slash character. If there are no slashes innamethen return.(a single dot). If the last slash innameis its first character, then return/. -
file executable name -
Return 1 if file
nameis executable by the current user, 0 otherwise. -
file exists name -
Return 1 if file
nameexists and the current user has search privileges for the directories leading to it, 0 otherwise. -
file extension name -
Return all of the characters in
nameafter and including the last dot inname. If there is no dot innamethen return the empty string. -
file isdirectory name -
Return 1 if file
nameis a directory, 0 otherwise. -
file isfile name -
Return 1 if file
nameis a regular file, 0 otherwise. -
file join arg... -
Joins multiple path components. Note that if any components is an absolute path, the preceding components are ignored. Thus
"returnsfilejoin /tmp /root""/root". -
file link ?-hard|-symbolic? newname target -
Creates a hard link (default) or symbolic link from
newnametotarget. Note that the sense of this command is the opposite offilerenameandfilecopyand also ofln, but this is compatible with Tcl. An error is returned iftargetdoesn’t exist ornewnamealready exists. -
file lstat name varName -
Same as stat option (see below) except uses the
lstatkernel call instead ofstat. This means that ifnamerefers to a symbolic link the information returned invarNameis for the link rather than the file it refers to. On systems that don’t support symbolic links this option behaves exactly the same as the stat option. -
file mkdir dir1 ?dir2...? -
Creates each directory specified. For each pathname
dirspecified, this command will create all non-existing parent directories as well asdiritself. If an existing directory is specified, then no action is taken and no error is returned. Trying to overwrite an existing file with a directory will result in an error. Arguments are processed in the order specified, halting at the first error, if any. -
file mtime name ?time? -
Return a decimal string giving the time at which file
namewas last modified. The time is measured in the standard UNIX fashion as seconds from a fixed starting time (often January 1, 1970). If the file doesn’t exist or its modified time cannot be queried then an error is generated. Iftimeis given, sets the modification time of the file to the given value. -
file mtimeus name ?time_us? -
As for
filemtimeexcept the time value is in microseconds since the epoch (see alsoclockmicroseconds). Note that some platforms and some filesystems don’t support high resolution timestamps for files. -
file normalize name -
Return the normalized path of
name. See realpath(3). -
file owned name -
Return 1 if file
nameis owned by the current user, 0 otherwise. -
file readable name -
Return 1 if file
nameis readable by the current user, 0 otherwise. -
file readlink name -
Returns the value of the symbolic link given by
name(i.e. the name of the file it points to). Ifnameisn’t a symbolic link or its value cannot be read, then an error is returned. On systems that don’t support symbolic links this option is undefined. -
file rename ?-force? oldname newname -
Renames the file from the old name to the new name. If
newnamealready exists, an error is returned unless-forceis specified. -
file rootname name -
Return all of the characters in
nameup to but not including the last . character in the name. Ifnamedoesn’t contain a dot, then returnname. -
file size name -
Returns the size, in bytes, of the file
name. -
file split name -
Returns a list whose elements are the path components in
name. The first element of the list will have the same path type asname. All other elements will be relative. Path separators will be discarded. -
file stat name ?varName? -
Invoke the stat kernel call on
name, and return the result as a dictionary with the following keys: atime, ctime, dev, gid, ino, mode, mtime, nlink, size, type, uid, mtimeus (if supported - seefilemtimeus) Each element except type is a decimal string with the value of the corresponding field from the stat return structure; see the manual entry for stat for details on the meanings of the values. The type element gives the type of the file in the same form returned by the commandfiletype. IfvarNameis specified, it is taken to be the name of an array variable and the values are also stored into the array. -
file tail name -
Return all of the characters in
nameafter the last slash. Ifnamecontains no slashes then returnname. -
file tempfile ?template? -
Creates and returns the name of a unique temporary file. If
templateis omitted, a default template will be used to place the file in /tmp. See mkstemp(3) for the format of the template and security concerns. -
file type name -
Returns a string giving the type of file
name, which will be one offile,directory,characterSpecial,blockSpecial,fifo,link, orsocket. -
file writable name -
Return 1 if file
nameis writable by the current user, 0 otherwise.
The file commands that return 0/1 results are often used in
conditional or looping commands, for example:
if {![file exists foo]} {
error {bad file name}
} else {
...
}finalize
finalize reference ?command?
If command is omitted, returns the finalizer command for the given reference.
Otherwise, sets a new finalizer command for the given reference. command may be
the empty string to remove the current finalizer.
The reference must be a valid reference create with the ref
command.
See GARBAGE COLLECTION for more detail.
for
for start test next body
for is a looping command, similar in structure to the C for statement.
The start, next, and body arguments must be Tcl command strings,
and test is an expression string.
The for command first invokes the Tcl interpreter to execute start.
Then it repeatedly evaluates test as an expression; if the result is
non-zero it invokes the Tcl interpreter on body, then invokes the Tcl
interpreter on next, then repeats the loop. The command terminates
when test evaluates to 0.
If a continue command is invoked within body then any remaining
commands in the current execution of body are skipped; processing
continues by invoking the Tcl interpreter on next, then evaluating
test, and so on.
for returns an empty string.
foreach
foreach varName list body
foreach varList list ?varList2 list2 ...? body
In this command, varName is the name of a variable, list
is a list of values to assign to varName, and body is a
collection of Tcl commands.
For each field in list (in order from left to right), foreach assigns
the contents of the field to varName (as if the lindex command
had been used to extract the field), then calls the Tcl interpreter to
execute body.
If instead of being a simple name, varList is used, multiple assignments
are made each time through the loop, one for each element of varList.
For example, if there are two elements in varList and six elements in
the list, the loop will be executed three times.
If the length of the list doesn’t evenly divide by the number of elements
in varList, the value of the remaining variables in the last iteration
of the loop are undefined.
The break and continue statements may be invoked inside body,
with the same effect as in the for command.
foreach returns an empty string.
format
format formatString ?arg ...?
This command generates a formatted string in the same way as the
C sprintf procedure (it uses sprintf in its
implementation). formatString indicates how to format
the result, using % fields as in sprintf, and the additional
arguments, if any, provide values to be substituted into the result.
All of the sprintf options are valid; see the sprintf
man page for details. Each arg must match the expected type
from the % field in formatString; the format command
converts each argument to the correct type (floating, integer, etc.)
before passing it to sprintf for formatting.
The only unusual conversion is for %c; in this case the argument
must be a decimal string, which will then be converted to the corresponding
ASCII (or UTF-8) character value.
In addition, Jim Tcl provides basic support for conversion to binary with %b.
format does backslash substitution on its formatString
argument, so backslash sequences in formatString will be handled
correctly even if the argument is in braces.
The return value from format is the formatted string.
getref
getref reference
Returns the string associated with reference. The reference must
be a valid reference create with the ref command.
See GARBAGE COLLECTION for more detail.
glob
glob ?-nocomplain? ?-directory dir? ?-tails? ?--? pattern ?pattern ...?
This command performs filename globbing, using csh rules. The returned
value from glob is the list of expanded filenames.
If -nocomplain is specified as the first argument then an empty
list may be returned; otherwise an error is returned if the expanded
list is empty. The -nocomplain argument must be provided
exactly: an abbreviation will not be accepted.
If -directory is given, the dir is understood to contain a
directory name to search in. This allows globbing inside directories
whose names may contain glob-sensitive characters. The returned names
include the directory name unless -tails is specified.
If -tails is specified, along with -directory, the returned names
are relative to the given directory.
global
global varName ?varName ...?
This command is ignored unless a Tcl procedure is being interpreted.
If so, then it declares each given varName to be a global variable
rather than a local one. For the duration of the current procedure
(and only while executing in the current procedure), any reference to
varName will be bound to a global variable instead
of a local one.
An alternative to using global is to use the :: prefix
to explicitly name a variable in the global scope.
if
if expr1 ?then? body1 elseif expr2 ?then? body2 elseif ... ?else? ?bodyN?
The if command evaluates expr1 as an expression (in the same way
that expr evaluates its argument). The value of the expression must
be numeric; if it is non-zero then body1 is executed by passing it to
the Tcl interpreter.
Otherwise expr2 is evaluated as an expression and if it is non-zero
then body2 is executed, and so on.
If none of the expressions evaluates to non-zero then bodyN is executed.
The then and else arguments are optional "noise words" to make the
command easier to read.
There may be any number of elseif clauses, including zero. bodyN
may also be omitted as long as else is omitted too.
The return value from the command is the result of the body script that
was executed, or an empty string if none of the expressions was non-zero
and there was no bodyN.
incr
incr varName ?increment?
Increment the value stored in the variable whose name is varName.
The value of the variable must be integral.
If increment is supplied then its value (which must be an
integer expression) is added to the value of variable varName; otherwise
1 is added to varName.
The new value is stored as a decimal string in variable varName
and also returned as result.
If the variable does not exist, the variable is implicitly created
and set to 0 first.
info
-
info option ?arg...? -
Provide information about various internals to the Tcl interpreter. The legal
option's (which may be abbreviated) are: -
info args procname -
Returns a list containing the names of the arguments to procedure
procname, in order.procnamemust be the name of a Tcl command procedure. -
info alias command -
commandmust be an alias created withalias. In which case the target command and arguments, as passed toaliasare returned. Seeexists-alias -
info aliases ?-all? ?pattern? -
Returns a list of alias commands. See
infocommandsfor the meaning of-allandpattern. -
info body procname -
Returns the body of procedure
procname.procnamemust be the name of a Tcl command procedure. -
info channels ?-all? ?pattern? -
Returns a list of open file handles from
openorsocket. Seeinfocommandsfor the meaning of-allandpattern. -
info commands ?-all? ?pattern? -
If
patternisn’t specified, returns a list of names of all the Tcl commands, including both the built-in commands written in C and the command procedures defined using theproccommand (including aliases and channels). Ifpatternis specified, only those names matchingpattern(using STRING MATCHING rules) are returned. Normally commands containing a space character are not returned. If-allis given, the result does include these commands. -
info complete command ?missing? -
Returns 1 if
commandis a complete Tcl command in the sense of having no unclosed quotes, braces, brackets or array element names, If the command doesn’t appear to be complete then 0 is returned. This command is typically used in line-oriented input environments to allow users to type in commands that span multiple lines; if the command isn’t complete, the script can delay evaluating it until additional lines have been typed to complete the command. IfvarNameis specified, the missing character is stored in the variable with that name. -
info exists varName -
Returns 1 if the variable named
varNameexists in the current context (either as a global or local variable), returns 0 otherwise. -
info frame ?number? -
Note: This command has changed as of Jim version 0.82 to be more Tcl-compatible.
-
If
numberis not specified, this command returns a number giving the evaluation level of the invoking command (1 when invoked a the top level). -
If
numberis positive then it selects a particular evaluation level (1 refers to the top-most evaluation level, 2 to the command it called, and so on); otherwise it gives a level relative to the current evaluation level (0 refers to the current command (info frame), -1 to its caller, and so on). In this case, the command returns a dictionary containing the folllowing keys: -
type - always
"source" -
file - file name where the command was invoked (may be empty if not known)
-
line - line number where the command was invoked (may be 0 if not known)
-
cmd - the command (as a list) executing at the given level
-
proc - if within a proc, the name of the proc (omitted if not within a proc)
-
level - the evaluation level
-
info globals ?pattern? -
If
patternisn’t specified, returns a list of all the names of currently-defined global variables. Ifpatternis specified, only those names matchingpattern(using STRING MATCHING rules) are returned. -
info hostname -
An alias for
os.gethostnamefor compatibility with Tcl 6.x -
info level ?number? -
If
numberis not specified, this command returns a number giving the stack level of the invoking procedure, or 0 if the command is invoked at top-level. Ifnumberis specified, then the result is a list consisting of the name and arguments for the procedure call at levelnumberon the stack. Ifnumberis positive then it selects a particular stack level (1 refers to the top-most active procedure, 2 to the procedure it called, and so on); otherwise it gives a level relative to the current level (0 refers to the current procedure, -1 to its caller, and so on). See theuplevelcommand for more information on what stack levels mean. -
info locals ?pattern? -
If
patternisn’t specified, returns a list of all the names of currently-defined local variables, including arguments to the current procedure, if any. Variables defined with theglobalandupvarcommands will not be returned. Ifpatternis specified, only those names matchingpattern(using STRING MATCHING rules) are returned. -
info nameofexecutable -
Returns the name of the binary file from which the application was invoked. A full path will be returned, unless the path can’t be determined, in which case the empty string will be returned.
-
info patchlevel -
Returns the build (git) version if available. Otherwise returns the same as
infoversion. -
info procs ?-all? ?pattern? -
Returns a list containing the names of Tcl command procedures. See
infocommandsfor the meaning of-allandpattern. -
info references -
Returns a list of all references which have not yet been garbage collected.
-
info returncodes ?code? -
Returns a list representing the mapping of standard return codes to names. e.g.
{0 ok 1 error 2 return ...}. If a code is given, instead returns the name for the given code. -
info script -
If a Tcl script file is currently being evaluated (i.e. there is a call to Jim_EvalFile active or there is an active invocation of the
sourcecommand), then this command returns the name of the innermost file being processed. Otherwise the command returns an empty string. -
info source script ?filename line? -
With a single argument, returns the original source location of the given script as a list of
{filename linenumber}. If the source location can’t be determined, the list{{} 0}is returned. Iffilenameandlineare given, returns a copy ofscriptwith the associate source information. This can be useful to produce useful messages fromeval, etc. if the original source information may be lost. -
info stacktrace -
After an error is caught with
catch, returns the stack trace as a list of{procedure filename line cmd ...}. -
info statics procname -
Returns a dictionary of the static variables of procedure
procname.procnamemust be the name of a Tcl command procedure. An empty dictionary is returned if the procedure has no static variables. -
info tainted str -
Returns 1 if the value is tainted, or 0 if not.
-
info usage command -
Returns the usage for the given command. For Tcl command procedures, this is based on the arguments defined for the procedure. For a C command, this is the command usage that was specificied when the command was registered.
-
info version -
Returns the version number for this version of Jim in the form
x.yy. -
info vars ?pattern? -
If
patternisn’t specified, returns a list of all the names of currently-visible variables, including both locals and currently-visible globals. Ifpatternis specified, only those names matchingpattern(using STRING MATCHING rules) are returned.
join
join list ?joinString?
The list argument must be a valid Tcl list. This command returns the
string formed by joining all of the elements of list together with
joinString separating each adjacent pair of elements.
The joinString argument defaults to a space character.
kill
kill ?SIG|-0? pid
Sends the given signal to the process identified by pid.
The signal may be specified by name or number in one of the following forms:
-
TERM -
SIGTERM -
-TERM -
15 -
-15
The signal name may be in either upper or lower case.
The special signal name -0 simply checks that a signal could be sent.
If no signal is specified, SIGTERM is used.
An error is raised if the signal could not be delivered.
lambda
lambda args ?statics? body
The lambda command is identical to proc, except rather than
creating a named procedure, it creates an anonymous procedure and returns
the name of the procedure.
See proc and GARBAGE COLLECTION for more detail.
lappend
lappend varName value ?value value ...?
Treat the variable given by varName as a list and append each of
the value arguments to that list as a separate element, with spaces
between elements.
If varName doesn’t exist, it is created as a list with elements given
by the value arguments. lappend is similar to append except that
each value is appended as a list element rather than raw text.
This command provides a relatively efficient way to build up large lists. For example,
lappend a $bis much more efficient than
set a [concat $a [list $b]]when $a is long.
lassign
lassign list varName ?varName ...?
This command treats the value list as a list and assigns successive elements from that list to
the variables given by the varName arguments in order. If there are more variable names than
list elements, the remaining variables are set to the empty string. If there are more list elements
than variables, a list of unassigned elements is returned.
. lassign {1 2 3} a b; puts a=$a,b=$b
3
a=1,b=2lsubst
lsubst ?-line? string
This command is similar to list in that it creates a list, but uses
the same rules as scripts when constructing the elements of the list.
It is somewhat similar to subst except it produces a list instead of a string.
This means that variables are substituted, commands are evaluated, backslashes are interpreted, the expansion operator is applied and comments are skipped.
Consider the following example.
--- set x 1 set y {2 3} set z 3 lsubst { # This is a list with interpolation $x; # The x variable {}$y; # The y variable expanded [string cat a b c]; # A command {}[list 4 5]; # A list expanded into multiple elements "$z$z"; # A string with interpolation } ---
The result of lsubst is the following list with 7 elements.
--- 1 2 3 abc 4 5 33 ---
This is particularly useful when constructing a list (or dict) as a data structure as it easily allows for comments and variable and command substitution.
Sometimes it is useful to return each "command" as a separate list rather than
simply running all the words together. This can be accomplished with lsubst -line.
Consider the following example.
--- lsubst -line { # two "lines" because of the semicolon one a; two b # one line with three elements {*}{a b c} } ---
The result of lsubst -line is the following list with 3 elements, one for each "command".
--- {one a} {two b} {a b c} ---
local
local cmd ?arg...?
First, local evaluates cmd with the given arguments. The return value must
be the name of an existing command, which is then marked as having local scope.
This means that when the current procedure exits, the specified
command is deleted. This can be useful with lambda, local procedures or
to automatically close a filehandle.
In addition, if a the command already exists with the same name,
the existing command will be kept rather than being deleted, and may be called
via upcall. The previous command will be restored when the current
procedure exits. See upcall for more details.
In this example, a local procedure is created. Note that the procedure continues to have global scope while it is active.
proc outer {} {
# proc ... returns "inner" which is marked local
local proc inner {} {
# will be deleted when 'outer' exits
}
inner
...
}In this example, the lambda is deleted at the end of the procedure rather
than waiting until garbage collection. Note that local returns the command name.
proc outer {} {
set x [local lambda {args} {
# will be deleted when 'outer' exits
}]
$x ...
...
}Also see defer as another mechanism for cleaning up at the end of a procedure.
loop
loop var ?first? limit ?incr? body
Similar to for except simpler and possibly more efficient.
If incr is positive, the effect is, equivalent to:
for {set var $first} {$var < $limit} {incr var $incr} $bodyWhile if incr is negative, the count is downwards.
If first is not specified, 0 is used.
If incr is not specified, 1 is used.
Note that setting the loop variable inside the loop does not
affect the loop count.
first, limit and incr may be any integer expression.
lindex
lindex list ?index …?
Treats list as a Tcl list and returns element index from it
(0 refers to the first element of the list).
See STRING AND LIST INDEX SPECIFICATIONS for all allowed forms for index.
In extracting the element, lindex observes the same rules concerning
braces and quotes and backslashes as the Tcl command interpreter; however,
variable substitution and command substitution do not occur.
If no index values are given, simply returns list
If index is negative or greater than or equal to the number of elements
in list, then an empty string is returned.
If additional index arguments are supplied, then each argument is used in turn to select an element from the previous indexing operation, allowing the script to select elements from sublists.
linsert
linsert list index element ?element element ...?
This command produces a new list from list by inserting all
of the element arguments just before the element index
of list. Each element argument will become
a separate element of the new list. If index is less than
or equal to zero, then the new elements are inserted at the
beginning of the list. If index is greater than or equal
to the number of elements in the list, then the new elements are
appended to the list.
See STRING AND LIST INDEX SPECIFICATIONS for all allowed forms for index.
list
list arg ?arg ...?
This command returns a list comprised of all the arguments, arg. Braces
and backslashes get added as necessary, so that the lindex command
may be used on the result to re-extract the original arguments, and also
so that eval may be used to execute the resulting list, with
arg1 comprising the command’s name and the other args comprising
its arguments. list produces slightly different results than
concat: concat removes one level of grouping before forming
the list, while list works directly from the original arguments.
For example, the command
list a b {c d e} {f {g h}}will return
a b {c d e} {f {g h}}while concat with the same arguments will return
a b c d e f {g h}llength
llength list
Treats list as a list and returns the number of elements in that list.
lset
lset varName ?index ..? newValue
Sets an element in a list.
The lset command accepts a parameter, varName, which it interprets
as the name of a variable containing a Tcl list. It also accepts
zero or more indices into the list. Finally, it accepts a new value
for an element of varName. If no indices are presented, the command
takes the form:
lset varName newValueIn this case, newValue replaces the old value of the variable
varName.
When presented with a single index, the lset command
treats the content of the varName variable as a Tcl list. It addresses
the index’th element in it (0 refers to the first element of the
list). When interpreting the list, lset observes the same rules
concerning braces and quotes and backslashes as the Tcl command
interpreter; however, variable substitution and command substitution
do not occur. The command constructs a new list in which the
designated element is replaced with newValue. This new list is
stored in the variable varName, and is also the return value from
the lset command.
If index is negative or greater than or equal to the number of
elements in $varName, then an error occurs.
See STRING AND LIST INDEX SPECIFICATIONS for all allowed forms for index.
If additional index arguments are supplied, then each argument is used in turn to address an element within a sublist designated by the previous indexing operation, allowing the script to alter elements in sublists. The command,
lset a 1 2 newValuereplaces element 2 of sublist 1 with newValue.
The integer appearing in each index argument must be greater than
or equal to zero. The integer appearing in each index argument must
be strictly less than the length of the corresponding list. In other
words, the lset command cannot change the size of a list. If an
index is outside the permitted range, an error is reported.
lmap
lmap varName list body
lmap varList list ?varList2 list2 ...? body
For example:
. lmap i {1 2 3 4 5} {expr $i*$i}
1 4 9 16 25
. lmap a {1 2 3} b {A B C} {list $a $b}
{1 A} {2 B} {3 C}load
load filename
Loads the dynamic extension, filename. Generally the filename should have
the extension .so. The initialisation function for the module must be based
on the name of the file. For example loading hwaccess.so will invoke
the initialisation function, Jim_hwaccessInit. Normally the load command
should not be used directly. Instead it is invoked automatically by package require.
lrange
lrange list first last
list must be a valid Tcl list. This command will return a new
list consisting of elements first through last, inclusive.
See STRING AND LIST INDEX SPECIFICATIONS for all allowed forms for first and last.
If last is greater than or equal to the number of elements
in the list, then it is treated as if it were end.
If first is greater than last then an empty string
is returned.
lreplace
lreplace list first last ?element element ...?
Returns a new list formed by replacing one or more elements of
list with the element arguments.
first gives the index in list of the first element
to be replaced.
If first is less than zero then it refers to the first
element of list; the element indicated by first
must exist in the list.
last gives the index in list of the last element
to be replaced; it must be greater than or equal to first.
See STRING AND LIST INDEX SPECIFICATIONS for all allowed forms for first and last.
The element arguments specify zero or more new arguments to
be added to the list in place of those that were deleted.
Each element argument will become a separate element of
the list.
If no element arguments are specified, then the elements
between first and last are simply deleted.
lrepeat
lrepeat number element1 ?element2 ...?
Build a list by repeating elements number times (which must be
a positive integer).
. lrepeat 3 a b
a b a b a blreverse
lreverse list
Returns the list in reverse order.
. lreverse {1 2 3}
3 2 1lsearch
lsearch ?options? list pattern
This command searches the elements list to see if one of them matches pattern. If so, the
command returns the index of the first matching element (unless the options -all, -inline or -bool are
specified.) If not, the command returns -1. The option arguments indicates how the elements of
the list are to be matched against pattern and must have one of the values below:
Note that this command is different from Tcl in that default match type is -exact rather than -glob.
-
-exact -
patternis a literal string that is compared for exact equality against each list element. This is the default. -
-glob -
patternis a glob-style pattern which is matched against each list element using STRING MATCHING rules. -
-regexp -
patternis treated as a regular expression and matched against each list element using REGULAR EXPRESSIONS rules. -
-command cmdname -
cmdnameis a command which is used to match the pattern against each element of the list. It is invoked ascmdname ?-nocase? pattern listvalueand should return 1 for a match, or 0 for no match. -
-all -
Changes the result to be the list of all matching indices (or all matching values if
-inlineis specified as well). If indices are returned, the indices will be in numeric order. If values are returned, the order of the values will be the order of those values within the input list. -
-inline -
The matching value is returned instead of its index (or an empty string if no value matches). If
-allis also specified, then the result of the command is the list of all values that matched. The-inlineand-booloptions are mutually exclusive. -
-bool -
Changes the result to 1 if a match was found, or 0 otherwise. If
-allis also specified, the result will be a list of 0 and 1 for each element of the list depending upon whether the corresponding element matches. The-inlineand-booloptions are mutually exclusive. -
-not -
This negates the sense of the match, returning the index (or value if
-inlineis specified) of the first non-matching value in the list. If-boolis also specified, the 0 will be returned if a match is found, or 1 otherwise. If-allis also specified, non-matches will be returned rather than matches. -
-nocase -
Causes comparisons to be handled in a case-insensitive manner.
-
-index indexList -
This option is designed for use when searching within nested lists. The indexList gives a path of indices (much as might be used with the lindex or lset commands) within each element to allow the location of the term being matched against.
-
-stride strideLength -
If this option is specified, the list is treated as consisting of groups of strideLength elements and the groups are searched by either their first element or, if the
-indexoption is used, by the element within each group given by the first index passed to-index(which is then ignored by-index). The resulting index always points to the first element in a group. -
The list length must be an integer multiple of strideLength, which in turn must be at least 1. A strideLength of 1 is the default and indicates no grouping.
lsort
lsort ?options? list
Sort the elements of list, returning a new list in sorted order.
By default, ASCII (or UTF-8) sorting is used, with the result in increasing order.
Note that only one sort type may be selected with -ascii, -dict, -integer, -real, -nocase or -command
with last option being used.
-
-ascii -
Sort using string comparison. This is the default.
-
-nocase -
Sort using using string comparison without regard for case.
-
-dict -
Sort using using string comparison without regard for case. Use dictionary-style comparison. This is the same as -ascii except (a) case is ignored except as a tie-breaker and (b) if two strings contain embedded numbers, the numbers compare as integers, not characters. For example, in -dictionary mode, x10y sorts between x9y and x11y.
-
-integer -
Sort using numeric (integer) comparison.
-
-real -
Sort using floating point comparison.
-
-command cmdname -
cmdnameis treated as a command name. For each comparison,cmdname $value1 $value2is called which should compare the values and return an integer less than, equal to, or greater than zero if the$value1is to be considered less than, equal to, or greater than$value2, respectively. -
-increasing -
The resulting list is in ascending order, from smallest/lowest to largest/highest. This is the default and does not need to be specified.
-
-decreasing -
The resulting list is in the opposite order to what it would be otherwise.
-
-unique -
Only the last set of duplicate elements found in the list will be retained. Note that duplicates are determined relative to the comparison used in the sort. Thus if
-index 0is used,{1 a}and{1 b}would be considered duplicates and only the second element,{1 b}, would be retained. -
-index indexList -
This option is designed for use when sorting nested lists. The indexList gives a path of indices (much as might be used with the lindex or lset commands) within each element to specify the value to be used for comparison.
-
-stride strideLength -
If this option is specified, the list is treated as consisting of groups of strideLength elements and the groups are sorted by either their first element or, if the
-indexoption is used, by the element within each group given by the first index passed to-index(which is then ignored by-index). The resulting list is once again a flat list. -
The list length must be an integer multiple of strideLength, which in turn must be at least 2.
open
open fileName ?-noclose? ?access?
open |command-pipeline ?access?
Opens a file and returns an identifier
that may be used in future invocations
of commands like read, puts, and close.
fileName gives the name of the file to open.
If -noclose is given, the returned handle is not automatically
closed for child proceses.
The access argument indicates the way in which the file is to be accessed.
It may have any of the following values:
-
r -
Open the file for reading only; the file must already exist.
-
r+ -
Open the file for both reading and writing; the file must already exist.
-
w -
Open the file for writing only. Truncate it if it exists. If it doesn’t exist, create a new file.
-
w+ -
Open the file for reading and writing. Truncate it if it exists. If it doesn’t exist, create a new file.
-
a -
Open the file for writing only. The file must already exist, and the file is positioned so that new data is appended to the file.
-
a+ -
Open the file for reading and writing. If the file doesn’t exist, create a new empty file. Set the initial access position to the end of the file.
access defaults to r.
Additionally, if POSIX mode is supported by the underlying system, then access may insted of consistent of a list of any of the following flags, all of which have the standard POSIX meanings. In this case, the first flag must be one of RDONLY, WRONLY or RDWR.
-
RDONLY -
Open the file for reading only.
-
WRONLY -
Open the file for writing only.
-
RDWR -
Open the file for both reading and writing.
-
APPEND -
Set the file pointer to the end of the file prior to each write.
-
BINARY -
Ignored.
-
CREAT -
Create the file if it does not already exist (without this flag it is an error for the file not to exist).
-
EXCL -
If CREAT is also specified, an error is returned if the file already exists.
-
NOCTTY -
If the file is a terminal device, this flag prevents the file from becoming the controlling terminal of the process.
-
TRUNC -
If the file exists it is truncated to zero length.
If a file is opened for both reading and writing, then seek
must be invoked between a read and a write, or vice versa.
If the first character of fileName is "|" then the remaining
characters of fileName are treated as a list of arguments that
describe a command pipeline to invoke, in the same style as the
arguments for exec. In this case, the channel identifier returned
by open may be used to write to the command’s input pipe or read
from its output pipe, depending on the value of access. If write-only
access is used (e.g. access is w), then standard output for the
pipeline is directed to the current standard output unless overridden
by the command. If read-only access is used (e.g. access is r),
standard input for the pipeline is taken from the current standard
input unless overridden by the command.
Note that this incudes new style exec syntax, e.g. open |[list | ls -l] r.
The pid command may be used to return the process ids of the commands
forming the command pipeline.
package
-
package forget ?name …? -
Removes the knowledge that the given packages were loaded. This allows new, replacement packages to be loaded. Note that it does not remove any effects of the previous packages being loaded.
-
package provide name ?version? -
Indicates that the current script provides the package named
name. Note: The supplied version is ignored. All packages are registered as version 1.0 (it is simply accepted for compatibility purposes). -
Any script that provides a package may include this statement as the first statement, although it is not required.
-
package require name ?version? -
Searches for the package with the given
nameby examining each path in $::auto_path and trying to load $path/$name.so as a dynamic extension, or $path/$name.tcl as a script package. -
The first such file which is found is considered to provide the package. (The version number is ignored).
-
If $name.so exists, it is loaded with the
loadcommand, otherwise if $name.tcl exists it is loaded with thesourcecommand. -
If
loadorsourcefails,packagerequirewill fail immediately. No further attempt will be made to locate the file. -
package names -
Returns a list of all known/loaded packages, including internal packages.
pid
pid
pid fileId
The first form returns the process identifier of the current process.
proc
proc name args ?statics? body
The proc command creates a new Tcl command procedure, name.
When the new command is invoked, the contents of body will be executed.
Tcl interpreter. args specifies the formal arguments to the procedure.
If specified, statics, declares static variables which are bound to the
procedure.
See PROCEDURES for detailed information about Tcl procedures.
When a procedure is invoked, the procedure’s return value is the
value specified in a return command. If the procedure doesn’t
execute an explicit return, then its return value is the value
of the last command executed in the procedure’s body.
If an error occurs while executing the procedure body, then the procedure-as-a-whole will return that same error.
puts
puts ?-nonewline? ?fileId? string
Tcl-compatible version of fileId puts ?-nonewline? string
See aio puts
pipe
Creates a pair of aio channels and returns the handles as a list: {read write}
lassign [pipe] r w
# Must close $w after exec
exec ps >@$w &
$w close
$r readable ...Note that if -noclose is desired, use socket -noclose pipe instead.
pwd
pwd
Returns the path name of the current working directory.
rand
rand ?min? ?max?
Returns a random integer between min (defaults to 0) and max
(defaults to the maximum integer).
If only one argument is given, it is interpreted as max.
range
range ?start? end ?step?
Returns a list of integers starting at start (defaults to 0)
and ranging up to but not including end in steps of step defaults to 1).
. range 5
0 1 2 3 4
. range 2 5
2 3 4
. range 2 10 4
2 6
. range 7 4 -2
7 5Integer parameters may be any integer expression.
read
read ?-nonewline? fileId ?length?
Tcl-compatible alterative version of fileId read ?-nonewline? ?length?
See aio read
regexp
regexp ?-nocase? ?-line? ?-indices? ?-start offset? ?-all? ?-inline? ?-expanded? ?--? exp string ?matchVar? ?subMatchVar subMatchVar ...?
Determines whether the regular expression exp matches part or
all of string and returns 1 if it does, 0 if it doesn’t.
See REGULAR EXPRESSIONS above for complete information on the
syntax of exp and how it is matched against string.
If additional arguments are specified after string then they
are treated as the names of variables to use to return
information about which part(s) of string matched exp.
matchVar will be set to the range of string that
matched all of exp. The first subMatchVar will contain
the characters in string that matched the leftmost parenthesized
subexpression within exp, the next subMatchVar will
contain the characters that matched the next parenthesized
subexpression to the right in exp, and so on.
Normally, matchVar and the each subMatchVar are set to hold the
matching characters from string, however see -indices and
-inline below.
If there are more values for subMatchVar than parenthesized subexpressions
within exp, or if a particular subexpression in exp doesn’t
match the string (e.g. because it was in a portion of the expression
that wasn’t matched), then the corresponding subMatchVar will be
set to "-1 -1" if -indices has been specified or to an empty
string otherwise.
The following switches modify the behaviour of regexp
-
-nocase -
Causes upper-case and lower-case characters to be treated as identical during the matching process.
-
-line -
Use newline-sensitive matching. By default, newline is a completely ordinary character with no special meaning in either REs or strings. With this flag,
[^bracket expressions and.never match newline, an^anchor matches the empty string after any newline in the string in addition to its normal function, and the$anchor matches the empty string before any newline in the string in addition to its normal function. -
-indices -
Changes what is stored in the subMatchVars. Instead of storing the matching characters from string, each variable will contain a list of two decimal strings giving the indices in string of the first and last characters in the matching range of characters.
-
-start offset -
Specifies a character index offset into the string at which to start matching the regular expression. If
-indicesis specified, the indices will be indexed starting from the absolute beginning of the input string.offsetwill be constrained to the bounds of the input string. -
-all -
Causes the regular expression to be matched as many times as possible in the string, returning the total number of matches found. If this is specified with match variables, they will contain information for the last match only.
-
-inline -
Causes the command to return, as a list, the data that would otherwise be placed in match variables. When using
-inline, match variables may not be specified. If used with-all, the list will be concatenated at each iteration, such that a flat list is always returned. For each match iteration, the command will append the overall match data, plus one element for each subexpression in the regular expression. -
-expanded -
Enables use of the expanded regular expression syntax where whitespace and comments are ignored.
-
-- -
Marks the end of switches. The argument following this one will be treated as
expeven if it starts with a-.
regsub
regsub ?-nocase? ?-all? ?-line? ?-command? ?-expanded? ?-start offset? ?--? exp string subSpec ?varName?
This command matches the regular expression exp against
string using the rules described in REGULAR EXPRESSIONS
above.
If varName is specified, the commands stores string to varName
with the substitutions detailed below, and returns the number of
substitutions made (normally 1 unless -all is specified).
This is 0 if there were no matches.
If varName is not specified, the substituted string will be returned
instead.
When copying string, the portion of string that
matched exp is replaced with subSpec.
If subSpec contains a & or \0, then it is replaced
in the substitution with the portion of string that
matched exp.
If subSpec contains a \n, where n is a digit
between 1 and 9, then it is replaced in the substitution with
the portion of string that matched the n'-th
parenthesized subexpression of exp.
Additional backslashes may be used in subSpec to prevent special
interpretation of & or \0 or \n or
backslash.
The use of backslashes in subSpec tends to interact badly
with the Tcl parser’s use of backslashes, so it’s generally
safest to enclose subSpec in braces if it includes
backslashes.
The following switches modify the behaviour of regsub
-
-nocase -
Upper-case characters in
stringare converted to lower-case before matching againstexp; however, substitutions specified bysubSpecuse the original unconverted form ofstring. -
-all -
All ranges in
stringthat matchexpare found and substitution is performed for each of these ranges, rather than only the first. The&and\nsequences are handled for each substitution using the information from the corresponding match. -
-line -
Use newline-sensitive matching. By default, newline is a completely ordinary character with no special meaning in either REs or strings. With this flag,
[bracket expressions and.never match newline, ananchor matches the empty string after any newline in the string in addition to its normal function, and the$anchor matches the empty string before any newline in the string in addition to its normal function. -
-command -
Changes the handling of
subSpecso that it is not treated as a template for a substitution string and the substrings&and\nno longer have special meaning. InsteadsubSpecmust be a command prefix, that is, a non-empty list. The substring of string that matchesexp, and then each substring that matches each capturing sub-RE withinexp, are appended as additional elements to that list. (The items appended to the list are much like whatregexp-inlinewould return). The completed list is then evaluated as a Tcl command, and the result of that command is the substitution string. Any error or exception from command evaluation becomes an error or exception from the regsub command. -
If
-allis not also given, the command callback will be invoked at most once (exactly when the regular expression matches). If-allis given, the command callback will be invoked for each matched location, in sequence. The exact location indices that matched are not made available to the script. -
-start offset -
Specifies a character index offset into the string at which to start matching the regular expression.
offsetwill be constrained to the bounds of the input string. -
-expanded -
Enables use of the expanded regular expression syntax where whitespace and comments are ignored.
-
-- -
Marks the end of switches. The argument following this one will be treated as
expeven if it starts with a-.
ref
ref string tag ?finalizer?
Create a new reference containing string of type tag.
If finalizer is specified, it is a command which will be invoked
when the a garbage collection cycle runs and this reference is
no longer accessible.
The finalizer is invoked as:
finalizer reference stringSee GARBAGE COLLECTION for more detail.
rename
rename oldName newName
Rename the command that used to be called oldName so that it
is now called newName. If newName is an empty string
(e.g. {}) then oldName is deleted. The rename command
returns an empty string as result.
return
return ?-code code? ?-errorinfo stacktrace? ?-errorcode errorcode? ?-level n? ?value?
Return immediately from the current procedure (or top-level command
or source command), with value as the return value. If value
is not specified, an empty string will be returned as result.
If -code is specified (as either a number or ok, error, break,
continue, signal, return or exit), this code will be used instead
of JIM_OK. This is generally useful when implementing flow of control
commands.
If -level is specified and greater than 1, it has the effect of delaying
the new return code from -code. This is useful when rethrowing an error
from catch. See the implementation of try/catch in tclcompat.tcl for
an example of how this is done.
Note: The following options are only used when -code is JIM_ERR.
If -errorinfo is specified (as returned from info stacktrace)
it is used to initialize the stacktrace.
If -errorcode is specified, it is used to set the global variable $::errorCode.
scan
scan string format varName1 ?varName2 ...?
This command parses fields from an input string in the same fashion
as the C sscanf procedure. string gives the input to be parsed
and format indicates how to parse it, using % fields as in
sscanf. All of the sscanf options are valid; see the sscanf
man page for details. Each varName gives the name of a variable;
when a field is scanned from string, the result is converted back
into a string and assigned to the corresponding varName. The
only unusual conversion is for %c. For %c conversions a single
character value is converted to a decimal string, which is then
assigned to the corresponding varName; no field width may be
specified for this conversion.
set
set varName ?value?
Returns the value of variable varName.
If value is specified, then set the value of varName to value,
creating a new variable if one doesn’t already exist, and return
its value.
If varName contains an open parenthesis and ends with a
close parenthesis, then it refers to an array element: the characters
before the open parenthesis are the name of the array, and the characters
between the parentheses are the index within the array.
Otherwise varName refers to a scalar variable.
If no procedure is active, then varName refers to a global
variable.
If a procedure is active, then varName refers to a parameter
or local variable of the procedure, unless the global command
has been invoked to declare varName to be global.
The :: prefix may also be used to explicitly reference a variable
in the global scope.
setref
setref reference string
Store a new string in reference, replacing the existing string.
The reference must be a valid reference create with the ref
command.
See GARBAGE COLLECTION for more detail.
signal
Command for signal handling.
See kill for the different forms which may be used to specify signals.
Commands which return a list of signal names do so using the canonical form:
"SIGINT SIGTERM".
-
signal handle ?signals ...? -
If no signals are given, returns a list of all signals which are currently being handled. If signals are specified, these are added to the list of signals currently being handled.
-
signal ignore ?signals ...? -
If no signals are given, returns a lists all signals which are currently being ignored. If signals are specified, these are added to the list of signals currently being ignored. These signals are still delivered, but are not considered by
catch-signalortry-signal. Usesignalcheckto determine which signals have occurred but been ignored. -
signal block ?signals ...? -
If no signals are given, returns a lists all signals which are currently being blocked. If signals are specified, these are added to the list of signals currently being blocked. These signals are not delivered to the process. This can be useful for signals such as
SIGPIPE, especially in conjunction withexecas child processes inherit the parent’s signal disposition. -
signal default ?signals ...? -
If no signals are given, returns a lists all signals which currently have the default behaviour. If signals are specified, these are added to the list of signals which have the default behaviour.
-
signal check ?-clear? ?signals ...? -
Returns a list of signals which have been delivered to the process but are ignored. If signals are specified, only that set of signals will be checked, otherwise all signals will be checked. If
-clearis specified, any signals returned are removed and will not be returned by subsequent calls tosignalcheckunless delivered again. -
signal throw ?signal? -
Raises the given signal, which defaults to
SIGINTif not specified. The behaviour is identical to:
kill signal [pid]Note that signal handle and signal ignore represent two forms of signal
handling. signal handle is used in conjunction with catch -signal or try -signal
to immediately abort execution when the signal is delivered. Alternatively, signal ignore
is used in conjunction with signal check to handle signal synchronously. Consider the
two examples below.
Prevent a processing from taking too long
signal handle SIGALRM
alarm 20
try -signal {
.. possibly long running process ..
alarm 0
} on signal {sig} {
puts stderr "Process took too long"
}Handle SIGHUP to reconfigure:
signal ignore SIGHUP
while {1} {
... handle configuration/reconfiguration ...
while {[signal check -clear SIGHUP] eq ""} {
... do processing ..
}
# Received SIGHUP, so reconfigure
}Note: signal handling is currently not supported in child interpreters. In these interpreters, the signal command does not exist.
sleep
sleep seconds
Pauses for the given number of seconds, which may be a floating point value less than one to sleep for less than a second, or an integer to sleep for one or more seconds.
source
source fileName
Read file fileName and pass the contents to the Tcl interpreter
as a sequence of commands to execute in the normal fashion. The return
value of source is the return value of the last command executed
from the file. If an error occurs in executing the contents of the
file, then the source command will return that error.
split
split string ?splitChars?
Returns a list created by splitting string at each character
that is in the splitChars argument.
Each element of the result list will consist of the
characters from string between instances of the
characters in splitChars.
Empty list elements will be generated if string contains
adjacent characters in splitChars, or if the first or last
character of string is in splitChars.
If splitChars is an empty string then each character of
string becomes a separate element of the result list.
splitChars defaults to the standard white-space characters.
For example,
split "comp.unix.misc" .returns "comp unix misc" and
split "Hello world" {}returns "H e l l o { } w o r l d".
stackdump
stackdump stacktrace
Creates a human readable representation of a stack trace.
stacktrace
stacktrace
Returns a live stack trace as a list of proc file line cmd proc file line cmd ....
uses the same information as info frame to create the stack trace. This stack trace is in the
same form as produced by catch and info stacktrace
See also stackdump.
string
string option arg ?arg ...?
Perform one of several string operations, depending on option.
The legal options (which may be abbreviated) are:
-
string bytelength string -
Returns the length of the string in bytes. This will return the same value as
stringlengthif UTF-8 support is not enabled, or if the string is composed entirely of ASCII characters. See UTF-8 AND UNICODE. -
string byterange string first last -
Like
stringrangeexcept works on bytes rather than characters. These commands are identical if UTF-8 support is not enabled. -
string cat ?string1 string2 ...? -
Concatenates the given strings into a single string.
-
string compare ?-nocase? ?-length len? string1 string2 -
Perform a character-by-character comparison of strings
string1andstring2in the same way as the C strcmp procedure. Return -1, 0, or 1, depending on whetherstring1is lexicographically less than, equal to, or greater thanstring2. If-lengthis specified, then only the firstlencharacters are used in the comparison. Iflenis negative, it is ignored. Performs a case-insensitive comparison if-nocaseis specified. -
string equal ?-nocase? ?-length len? string1 string2 -
Returns 1 if the strings are equal, or 0 otherwise. If
-lengthis specified, then only the firstlencharacters are used in the comparison. Iflenis negative, it is ignored. Performs a case-insensitive comparison if-nocaseis specified. -
string first string1 string2 ?firstIndex? -
Search
string2for a sequence of characters that exactly match the characters instring1. If found, return the index of the first character in the first such match withinstring2. If not found, return -1. IffirstIndexis specified, matching will start fromfirstIndexofstring1. -
See STRING AND LIST INDEX SPECIFICATIONS for all allowed forms for
firstIndex. -
string index string charIndex -
Returns the
charIndexth character of the'stringargument. AcharIndexof 0 corresponds to the first character of the string. IfcharIndexis less than 0 or greater than or equal to the length of the string then an empty string is returned. -
See STRING AND LIST INDEX SPECIFICATIONS for all allowed forms for
charIndex. -
string is class ?-strict? string -
Returns 1 if
stringis a valid member of the specified character class, otherwise returns 0. If-strictis specified, then an empty string returns 0, otherwise an empty string will return 1 on any class. The following character classes are recognized (the class name can be abbreviated): -
-
alnum -
Any alphabet or digit character.
-
alpha -
Any alphabet character.
-
ascii -
Any character with a value less than 128 (those that are in the 7-bit ascii range).
-
boolean -
Any of the valid string formats for a boolean value in Tcl (0, false, no, off, 1, true, yes, on)
-
control -
Any control character.
-
digit -
Any digit character.
-
double -
Any of the valid forms for a double in Tcl, with optional surrounding whitespace. In case of under/overflow in the value, 0 is returned.
-
graph -
Any printing character, except space.
-
integer -
Any of the valid string formats for an integer value in Tcl, with optional surrounding whitespace.
-
lower -
Any lower case alphabet character.
-
print -
Any printing character, including space.
-
punct -
Any punctuation character.
-
space -
Any space character.
-
upper -
Any upper case alphabet character.
-
xdigit -
Any hexadecimal digit character ([0-9A-Fa-f]).
-
-
Note that string classification does
notrespect UTF-8. See UTF-8 AND UNICODE. -
Note that only
lowercaseboolean values are recognized (Tcl accepts any case). -
string last string1 string2 ?lastIndex? -
Search
string2for a sequence of characters that exactly match the characters instring1. If found, return the index of the first character in the last such match withinstring2. If there is no match, then return -1. IflastIndexis specified, only characters up tolastIndexofstring2will be considered in the match. -
See STRING AND LIST INDEX SPECIFICATIONS for all allowed forms for
lastIndex. -
string length string -
Returns a decimal string giving the number of characters in
string. If UTF-8 support is enabled, this may be different than the number of bytes. See UTF-8 AND UNICODE. -
string map ?-nocase? mapping string -
Replaces substrings in
stringbased on the key-value pairs inmapping, which is a list ofkey value key value ...as in the form returned byarrayget. Each instance of a key in the string will be replaced with its corresponding value. If-nocaseis specified, then matching is done without regard to case differences. Both key and value may be multiple characters. Replacement is done in an ordered manner, so the key appearing first in the list will be checked first, and so on.stringis only iterated over once, so earlier key replacements will have no affect for later key matches. For example,
string map {abc 1 ab 2 a 3 1 0} 1abcaababcabababc-
will return the string
01321221. -
Note that if an earlier key is a prefix of a later one, it will completely mask the later one. So if the previous example is reordered like this,
string map {1 0 ab 2 a 3 abc 1} 1abcaababcabababc-
it will return the string
02c322c222c. -
string match ?-nocase? pattern string -
See if
patternmatchesstringaccording to STRING MATCHING rules ; return 1 if it does, 0 if it doesn’t. The match is performed in a case-insensitive manner if-nocaseis specified. -
string range string first last -
Returns a range of consecutive characters from
string, starting with the character whose index isfirstand ending with the character whose index islast. An index of 0 refers to the first character of the string. -
See STRING AND LIST INDEX SPECIFICATIONS for all allowed forms for
firstandlast. -
If
firstis less than zero then it is treated as if it were zero, and iflastis greater than or equal to the length of the string then it is treated as if it wereend. Iffirstis greater thanlastthen an empty string is returned. -
string repeat string count -
Returns a new string consisting of
stringrepeatedcounttimes. -
string replace string first last ?newstring? -
Removes a range of consecutive characters from
string, starting with the character whose index isfirstand ending with the character whose index islast. Ifnewstringis specified, then it is placed in the removed character range. Iffirstis less than zero then it is treated as if it were zero, and iflastis greater than or equal to the length of the string then it is treated as if it wereend. Iffirstis greater thanlastor the length of the initial string, orlastis less than 0, then the initial string is returned untouched. -
string reverse string -
Returns a string that is the same length as
stringbut with its characters in the reverse order. -
string tolower string -
Returns a value equal to
stringexcept that all upper case letters have been converted to lower case. -
string totitle string -
Returns a value equal to
stringexcept that the first character is converted to title case (or upper case if there is no UTF-8 titlecase variant) and all remaining characters have been converted to lower case. -
string toupper string -
Returns a value equal to
stringexcept that all lower case letters have been converted to upper case. -
string trim string ?chars? -
Returns a value equal to
stringexcept that any leading or trailing characters from the set given bycharsare removed. Ifcharsis not specified then white space is removed (spaces, tabs, newlines, and carriage returns). -
string trimleft string ?chars? -
Returns a value equal to
stringexcept that any leading characters from the set given bycharsare removed. Ifcharsis not specified then white space is removed (spaces, tabs, newlines, and carriage returns). -
string trimright string ?chars? -
Returns a value equal to
stringexcept that any trailing characters from the set given bycharsare removed. Ifcharsis not specified then white space is removed (spaces, tabs, newlines, and carriage returns). Null characters are always removed.
subst
subst ?-nobackslashes? ?-nocommands? ?-novariables? string
This command performs variable substitutions, command substitutions, and backslash substitutions on its string argument and returns the fully-substituted result. The substitutions are performed in exactly the same way as for Tcl commands. As a result, the string argument is actually substituted twice, once by the Tcl parser in the usual fashion for Tcl commands, and again by the subst command.
If any of the -nobackslashes, -nocommands, or -novariables are
specified, then the corresponding substitutions are not performed.
For example, if -nocommands is specified, no command substitution
is performed: open and close brackets are treated as ordinary
characters with no special interpretation.
Note: expr shorthand $(...) is considered a variable substitution
and so is disabled by -novariables.
Note: when it performs its substitutions, subst does not give any
special treatment to double quotes or curly braces. For example,
the following script returns xyz {44}, not xyz \{$a}.
set a 44
subst {xyz {$a}}switch
switch ?options? string pattern body ?pattern body ...?
switch ?options? string {pattern body ?pattern body ...?}
The switch command matches its string argument against each of
the pattern arguments in order. As soon as it finds a pattern that
matches string it evaluates the following body and returns the
result of that evaluation. If the last pattern argument is default
then it matches anything. If no pattern argument matches string and
no default is given, then the switch command returns an empty string.
If the initial arguments to switch start with - then they are treated
as options. The following options are currently supported:
-
-exact -
Use exact matching when comparing string to a pattern. This is the default.
-
-glob -
When matching string to the patterns, use glob-style STRING MATCHING rules.
-
-regexp -
When matching string to the patterns, use REGULAR EXPRESSIONS rules.
-
-command commandname -
When matching string to the patterns, use the given command, which must be a single word. The command is invoked as commandname pattern string, or commandname -nocase pattern string and must return 1 if matched, or 0 if not.
-
-- -
Marks the end of options. The argument following this one will be treated as string even if it starts with a
-.
Two syntaxes are provided for the pattern and body arguments. The
first uses a separate argument for each of the patterns and commands;
this form is convenient if substitutions are desired on some of the
patterns or commands. The second form places all of the patterns
and commands together into a single argument; the argument must
have proper list structure, with the elements of the list being the
patterns and commands. The second form makes it easy to construct
multi-line switch commands, since the braces around the whole list
make it unnecessary to include a backslash at the end of each line.
Since the pattern arguments are in braces in the second form, no
command or variable substitutions are performed on them; this makes
the behaviour of the second form different than the first form in
some cases.
If a body is specified as - it means that the body for the next
pattern should also be used as the body for this pattern (if the
next pattern also has a body of - then the body after that is
used, and so on). This feature makes it possible to share a single
body among several patterns.
Below are some examples of switch commands:
switch abc a - b {format 1} abc {format 2} default {format 3}will return 2,
switch -regexp aaab {
^a.*b$ -
b {format 1}
a* {format 2}
default {format 3}
}will return 1, and
switch xyz {
a -
b {format 1}
a* {format 2}
default {format 3}
}will return 3.
tailcall
tailcall cmd ?arg...?
The tailcall command provides an optimised way of invoking a command whilst replacing
the current call frame. This is similar to exec in Bourne Shell.
The following are identical except the first immediately replaces the current call frame.
tailcall a b c return [uplevel 1 [list a b c]]tailcall is useful as a dispatch mechanism:
proc a {cmd args} {
tailcall sub_$cmd {*}$args
}
proc sub_cmd1 ...
proc sub_cmd2 ...taint
taint varname
Set "taint" on the value contained in the given variable.
throw
throw code ?msg?
This command throws an exception (return) code along with an optional message.
This command is mostly for convenient usage with try.
The command throw break is equivalent to break.
The command throw 20 message can be caught with an on 20 ... clause to try.
time
time command ?count?
This command will call the Tcl interpreter count
times to execute command (or once if count isn’t
specified). It will then return a string of the form
503 microseconds per iterationwhich indicates the average amount of time required per iteration, in microseconds.
Time is measured in elapsed time, not CPU time.
timerate
timerate script ?milliseconds?
Evaluates the given script continuously until at least milliseconds time has elapsed (defaults to 1000)
and returns a dictionary containing performance results. The dictionary contains the following:
-
us_per_iter - average elapsed time (microseconds) per iteration
-
iters_per_sec - estimated number of iterations per second
-
count - number of iterations performed
-
elapsed_us - elapsed time (microseconds)
Note that timerate attempts to subtract the overhead of timerate itself in the result, hence
the returned elapsed time will typically be less than the specified run time.
The following is an example result of using timerate:
. timerate {expr {pow(1.5,7)}} 2000
us_per_iter 0.09866879769 iters_per_sec 10134916.2391 count 13046627 elapsed_us 1287295try
try ?catchopts? tryscript ?on|trap match {?resultvar? ?optsvar?} handlerscript ...? ?finally finalscript?
The try command is provided as a convenience for exception handling.
This interpeter first evaluates tryscript under the effect of the catch
options catchopts (e.g. -signal -noexit --, see catch).
It then evaluates the script for the first matching on or trap
handler (there many be zero or more) based on the return code and
errorcode from the try section. For example a normal JIM_ERR
error will be matched by an on error handler.
Finally, any finalscript is evaluated.
The result of this command is the result of tryscript, except
in the case where an exception occurs in a matching on handler
script or the finally script, in which case the result is this
new exception.
For the on handler, match is a list of return codes either
as names (ok, error, break, etc.) or as integers.
For the trap handler, match is a list to match against
errorcode. For example, if the errorcode was
{CHILDKILLED 10627 SIGTERM}, then a match value of {CHILDKILLED}
would match.
If resultvar and optsvar are specified, they are set as for
catch before evaluating the matching handler.
For example:
set f [open input]
try -signal {
process $f
} on {continue break} {} {
error "Unexpected break/continue"
} trap CHILDKILLED {msg opts} {
puts "A child process died"
return {*}$opts $msg
} on error {msg opts} {
puts "Dealing with error"
return {*}$opts $msg
} on signal sig {
puts "Got signal: $sig"
} finally {
$f close
}If break, continue or error are raised, they are dealt with by the matching
handler. If an error occurred with an errorcode of CHILDKILLED, the trap
handler will be evaluated as it is specified before the on error handler.
In any case, the file will be closed via the finally clause.
unknown
unknown cmdName ?arg arg …?
This command doesn’t actually exist as part of Tcl, but Tcl will invoke it if it does exist.
If the Tcl interpreter encounters a command name for which there
is not a defined command, then Tcl checks for the existence of
a command named unknown.
If there is no such command, then the interpreter returns an error.
If the unknown command exists, then it is invoked with
arguments consisting of the fully-substituted name and arguments
for the original non-existent command.
The unknown command typically does things like searching
through library directories for a command procedure with the name
cmdName, or expanding abbreviated command names to full-length,
or automatically executing unknown commands as UNIX sub-processes.
unset
unset ?-nocomplain? ?--? ?name name …?
Remove variables.
Each name is a variable name, specified in any of the
ways acceptable to the set command.
If a name refers to an element of an array, then that
element is removed without affecting the rest of the array.
If a name consists of an array name with no parenthesized
index, then the entire array is deleted.
The unset command returns an empty string as result.
An error occurs if any of the variables doesn’t exist, unless -nocomplain is specified. The -- argument may be specified to stop option processing in case the variable name may be -nocomplain.
untaint
untaint varname
Remove "taint" from the value contained in the given variable.
upcall
upcall command ?args …?
May be used from within a proc defined as local proc in order to call
the previous, hidden version of the same command.
If there is no previous definition of the command, an error is returned.
uplevel
uplevel ?level? command ?command …?
All of the command arguments are concatenated as if they had
been passed to concat; the result is then evaluated in the
variable context indicated by level. uplevel returns
the result of that evaluation. If level is an integer, then
it gives a distance (up the procedure calling stack) to move before
executing the command. If level consists of # followed by
a number then the number gives an absolute level number. If level
is omitted then it defaults to 1. level cannot be
defaulted if the first command argument starts with a digit or #.
For example, suppose that procedure a was invoked
from top-level, and that it called b, and that b called c.
Suppose that c invokes the uplevel command. If level
is 1 or #2 or omitted, then the command will be executed
in the variable context of b. If level is 2 or #1
then the command will be executed in the variable context of a.
If level is 3 or #0 then the command will be executed
at top-level (only global variables will be visible).
The uplevel command causes the invoking procedure to disappear
from the procedure calling stack while the command is being executed.
In the above example, suppose c invokes the command
uplevel 1 {set x 43; d}where d is another Tcl procedure. The set command will
modify the variable x in b’s context, and 'd will execute
at level 3, as if called from b. If it in turn executes
the command
uplevel {set x 42}upvar
upvar ?level? otherVar myVar ?otherVar myVar …?
This command arranges for one or more local variables in the current procedure to refer to variables in an enclosing procedure call or to global variables.
level may have any of the forms permitted for the uplevel
command, and may be omitted if the first letter of the first otherVar
isn’t # or a digit (it defaults to 1).
For each otherVar argument, upvar makes the variable
by that name in the procedure frame given by level (or at
global level, if level is #0) accessible
in the current procedure by the name given in the corresponding
myVar argument.
The variable named by otherVar need not exist at the time of the
call; it will be created the first time myVar is referenced, just like
an ordinary variable.
upvar may only be invoked from within procedures.
upvar returns an empty string.
The upvar command simplifies the implementation of call-by-name
procedure calling and also makes it easier to build new control constructs
as Tcl procedures.
For example, consider the following procedure:
proc add2 name {
upvar $name x
set x [expr $x+2]
}wait
wait
wait -nohang pid
With no arguments, cleans up any processes started by exec ... & that have completed
(reaps zombie processes).
With one or two arguments, waits for a process by id, either returned by exec ... &
or by os.fork (if supported).
Waits for the process to complete, unless -nohang is specified, in which case returns
immediately if the process is still running.
Returns a list of 3 elements.
{NONE x x} if the process does not exist or has already been waited for, or
if -nohang is specified, and the process is still alive.
{CHILDSTATUS <pid> <exit-status>} if the process exited normally.
{CHILDKILLED <pid> <signal>} if the process terminated on a signal.
{CHILDSUSP <pid> none} if the process terminated for some other reason.
Note that on platforms supporting waitpid(2), pid can also be given special values such
as 0 or -1. See waitpid(2) for more detail.
while
while test body
The while command evaluates test as an expression
(in the same way that expr evaluates its argument).
The value of the expression must be numeric; if it is non-zero
then body is executed by passing it to the Tcl interpreter.
Once body has been executed then test is evaluated
again, and the process repeats until eventually test
evaluates to a zero numeric value. continue
commands may be executed inside body to terminate the current
iteration of the loop, and break
commands may be executed inside body to cause immediate
termination of the while command.
The while command always returns an empty string.
xtrace
xtrace command
Install an execution trace callback command. This is useful for implementing a debugger or tracing tool. On each command invocation, the given command is invoked as:
command proc|cmd filename line result command arglistproc or cmd indicates whether a command or a proc body is being executed.
filename and line indicate the location where the command was invoked.
result is the current interpreter result (from the previous command).
command and arglist indicate the command being executed.
While the callback is executing, any further execution traces are temporarily disabled.
If the callback returns JIM_OK or JIM_RETURN, the execution trace is reinstalled. Otherwise
the execution trace is removed.
If xtrace is called with an empty argument (""), any existing callback is removed.
OPTIONAL-EXTENSIONS
The following extensions may or may not be available depending upon what options were selected when Jim Tcl was built.
posix: os.fork, os.gethostname, os.getids, os.uptime, os.umask
-
os.fork -
Invokes fork(2) and returns the result.
-
os.gethostname -
Invokes gethostname(3) and returns the result.
-
os.getids -
Returns the various user/group ids for the current process.
. os.getids
uid 1000 euid 1000 gid 100 egid 100-
os.umask ?newmask? -
Set or return the current process umask(2). Returns the previous umask.
-
os.uptime -
Returns the number of seconds since system boot. See description of uptime in sysinfo(2).
ANSI I/O (aio) and EVENTLOOP API
In addition to the traditional Tcl I/O commands (gets, read, puts, close, seek, tell),
Jim provides an alternative object-based API for I/O. Commands that create a channel, open and socket,
return a handle to an I/O channel that is used to control that channel.
For example, the traditional Tcl usage would be:
set f [open file.txt]
while {[gets $f buf] >= 0} {
puts stderr $buf
}
close $fWhile the Jim usage would be:
set f [open file.txt]
while {[$f gets buf] >= 0} {
stderr puts $buf
}
$f closeThus channels are commands that support the various subcommands. They can be renamed handled
like any other command. In additional to file I/O and stream (TCP) sockets, Jim supports many
kinds of socket streams including UDP, Unix domain sockets, psuedo-tty pairs, pipes and others.
(See socket for more detail). The TLS (SSL) protocol may also be seamlessly layered over a channel
with the ssl command. In addition Jim I/O supports both blocking and non-blocking modes,
fully integrates with the eventloop, supports serial ports and tty control.
Note that while most channels are stream channels, some channels (socket types with dgram) are
datagram channels. For those channels, aio recv and aio sendto is generally preferable
over aio read and aio puts.
aio
-
$handle accept ?-noclose? ?addrvar? -
Server socket only: Accept a connection and return a stream channel. If
addrvaris specified, the address of the connected client is stored in the named variable in the form addr:port for IP sockets or path for Unix domain sockets. Seesocketfor details. If-nocloseis given, the returned handle is not automatically closed for child proceses. Seesocketfor details. -
$handle buffering none|line|full ?size? -
Sets the output buffering mode of the stream channel.
nonemeans that puts immediately writes output.linemeans output (including previously buffered output) is written if a newline is to be written.fullmeans that data is written when the output buffer is full (default 64KB). Size may be specified in full mode. Note that line buffering will also write once the output buffer limit is reached, even if there is no newline. Channels usually begin in full buffering mode, unless they identify as a tty channel, in which case line buffering is used, andstderrbegins with no buffering. Returns the current buffering mode (including size in full mode - e.g.lineorfull 65536. See alsoaioputsandaioflush. -
$handle close ?r(ead)|w(rite)? ?-nodelete? -
Closes the stream. The
readandwritearguments perform a "half-close" on a socket. See the shutdown(2) man page. The-nodeleteoption is applicable only for Unix domain sockets. It closes the socket but does not delete the bound path (e.g. afteros.fork). After a full close, the channel handle is no longer valid. -
$handle copyto $tohandle ?size? -
Copy bytes to channel
$tohandle. Ifsizeis specified, at most that many bytes will be copied. Otherwise copying continues until the end of the input channel. Returns the number of bytes actually copied. -
$handle eof -
Returns 1 if an end-of-file condition has occurred on the channel. Note that this condition may only be checked after reading from the channel.
-
$handle filename -
Returns the original filename associated with the handle. Handles returned by
socketprovide different information such as the peer address or a generic name if no useful filename can be provided. Seesocketfor each socket type. -
$handle flush -
Flushes any output that has been buffered for the channel. In blocking mode, command does not return until all data has been written. In non-blocking mode, the behaviour depends on whether an
aiowritablehandler has been set. If it has, and not all data could be written and error will be returned with the message "send buffer full". Otherwise an "autoflush" eventloop handler is installed to flush the remaining data. As long as the eventloop runs (vwait,update), the write data will be automatically flushed. -
$handle gets ?-eol str? ?-keep 0|1? ?varName? -
Read one line from the channel and return it or store it in the variable. A terminating newline character is discarded. If
varNameis specified, then the line is placed in the variable by that name and the return value is a count of the number of characters read (not including the newline). If the end of the file is reached before reading any characters then -1 is returned andvarNameis set to an empty string. IfvarNameis not specified then the return value will be the line (minus the newline character) or an empty string if the end of the file is reached before reading any characters. An empty string will also be returned if a line contains no characters except the newline, soeofmay have to be used to determine what really happened. If the last character in the file is not a newline character, thengetsbehaves as if there were an additional newline character at the end of the file. -
If
-eolis given, the end of line is considered to be the given string instead of the newline character. If-keep 1is given, the end-of-line string is not discarded and instead is returned as part of the result (and if the return value is the character count, it includes the end-of-line string). The default is-keep 0. -
$handle getfd -
Returns the underlying file descriptor. On Unix platforms this is a small integer.
-
$handle isatty -
Returns 1 if the channel is a tty device.
-
$handle lock ?-wait? -
Apply a POSIX lock to the open file associated with the channel using fcntl(F_SETLK), or fcntl(F_SETLKW) to wait for the lock to be available if
-waitis specified. The channel must be open for write access. Returns 1 if the lock was successfully obtained, 0 otherwise. An error occurs if the channel is not suitable for locking (e.g. if it is not open for write) -
$handle ndelay ?0|1? -
With no argument, returns the non-blocking status of the channel (1 means non-blocking). With an arguments, sets the non-blocking status of the channel.
-
$handle peername -
Returns the remote address or path of the connected socket. See getpeername(2).
-
$handle puts ?-nonewline? string -
Writes the characters given by
stringto the channel given With-nonewline, the string is written as-is to the channel. Otherwise a newline character is written after the string. Seeaiobufferingandaioflushfor how output is buffered. -
$handle read ?-nonewline|-pending|len?' -
Read and return bytes from the channel. If len is not given, reads until end-of-file. reading from non-blocking channels. For backward compatibility,
-pendingis accepted, but ignored. If the-nonewlineswitch is specified then the last character (at end-of-file) is discarded if it is a newline. Note that read on a non-blocking channel may read less than the expected number of bytes (including zero). Useaioeofto determine if the end-of-file has been reached. -
$handle readsize ?size?' -
Sets or returns the current size of the read buffer used for read, gets and copyto. Defaults to 256, but can be increased to improve performance for large reads.
-
$handle recvfrom maxlen ?addrvar? -
Receives a message from the datagram channel via recvfrom(2) and returns it. At most
maxlenbytes are read. Ifaddrvaris specified, the sending address of the message is stored in the named variable in the form addr:port for IP sockets or path for Unix domain sockets. Seesocketfor details. -
$handle seek offset ?start|current|end? -
Change the current access position for the channel. This is only applicable to regular files, not sockets. The
offsetandoriginarguments specify the position at which the next read or write will occur forfileId.offsetmust be a number (which may be negative) andoriginmust be one of the following: -
start -
The new access position will be
offsetbytes from the start of the file. -
current -
The new access position will be
offsetbytes from the current access position; a negativeoffsetmoves the access position backwards in the file. -
end -
The new access position will be
offsetbytes from the end of the file. A negativeoffsetplaces the access position before the end-of-file, and a positiveoffsetplaces the access position after the end-of-file.
The origin argument defaults to start.
This command returns an empty string.
-
$handle sendto str ?address -
Sends the string,
str, to the given address (host:port or path) via datagram socket channel using sendto(2). This is intended for udp/dgram sockets and may give an error or behave in unintended ways for other handle types. Returns the number of bytes written. -
$handle sockname -
Returns the bound address or path of the socket channel. See getsockname(2).
-
$handle stat ?varName? -
Implements the same functionality as
filestatfor a file channel. Only available on platforms that support fstat(2) or equivalent. -
$handle sockopt ?name value? -
With no arguments, returns a dictionary of socket options currently set for the socket channel (will be empty for a non-socket). With
nameandvalue, sets the socket option to the given value. Currently supports the following boolean socket options:broadcast, debug, keepalive, nosigpipe, oobinline, tcp_nodelay, and the following integer socket options:sndbuf, rcvbuf -
$handle sync -
Flushes the channel, then calls fsync(2) to commit any changes to storage. Only available on platforms that support fsync(2). If the flush fails (perhaps because the channel is non-blocking), an error will be returned instead. Although this is designed for normal files and those should be used in blocking mode.
-
$handle taint source|sink ?0:n? -
Sets the taint characteristics of the channel. Data read from the channel will have a taint value as set by
source, while a check will be made against data written to the channel against thesinkvalue. If the taint of the data and the channel match, the operation will fail. By default, channels created byopenare not tainted while channels created bysockethave both set to 1. -
$handle tell -
Returns the current seek position or -1 if the channel is not seekable.
-
$handle timeout ?ms? -
With no argument, returns the current timeout of the channel, in milliseconds. If an argument is given, it is set as the timeout of the channel, in milliseconds. See
aioreadandaiogetsfor command that use the timeout. Note that the timeout is only used if the channel is in blocking mode. -
$handle translation binary|text -
This has no effect on Unix platforms, but on Windows it changes the mode of the file handle to binary or text. In general, use "wb" as the open mode instead, but this can be useful on existing filehandles such as
stdoutandstderr. It is probably a good idea to do this immediately before sending any output. -
$handle tty ?settings? -
If no arguments are given, returns a dictionary containing the tty settings for the stream. If arguments are given, they must either be a dictionary, or
setting value .... Abbreviations are supported for both settings and values, so the following is acceptable:$f tty parity e input c out raw. Only available on platforms that support termios(3). Supported settings are:-
baud rate -
Baud rate. e.g. 115200
-
data 5|6|7|8 -
Number of data bits
-
stop 1|2 -
Number of stop bits
-
parity even|odd|none -
Parity setting
-
handshake xonxoff|rtscts|none -
Handshaking type
-
input raw|cooked -
Input character processing. In raw mode, the usual key sequences such as ^C do not generate signals.
-
output raw|cooked -
Output character processing. Typically CR → CRNL is disabled in raw mode.
-
echo 0|1 -
Disable or enable echo on input. Note that this is a set-only value. Setting
inputtoraworcookedwill overwrite this setting. -
vmin numchars -
Minimum number of characters to read.
-
vtime time -
Timeout for noncanonical read (units of 0.1 seconds)
-
vstart char -
Start character for xonoff, usually 0x11 (^Q)
-
vstop char -
Stop character for xonoff, usually 0x13 (^S)
-
-
$handle ttycontrol ?settings? -
If no arguments are given, returns a dictionary containing the modem control signals from the stream (must be a serial-type device). e.g.
{rts 1 dtr 1 dcd 0 dsr 0 ring 0 cts 0}. Note thatrtsanddtrare controlled by the local system while the other signals reflect the remote system. If arguments are given, they must either be a dictionary, orsetting value .... Abbreviations are supported for both settings and values. Supported settings are:-
rts 0|1 -
Set the RTS (Request To Send) signal
-
dtr 0|1 -
Set the DTR (Data Terminal Ready) signal
-
break duration -
Generate a break condition.
durationis generally ignored but may be used in a platform-dependent manner.
-
-
$handle ssl ?-server cert ?key?|-sni servername? -
Upgrades the stream to a SSL/TLS session and returns the handle. If
-serveris specified, either both the certificate and private key files must be specified, or a single file must be specified containing both. If-serveris not specified, the connection is a client connection. In this case-snimay be specified if required to set the Server Name Indication. -
$handle unlock -
Release a POSIX lock previously acquired by
aiolock. -
$handle verify -
Verifies the certificate of a SSL/TLS stream peer
-
load_ssl_certs dir -
Loads SSL/TLS CA certificates for use during verification
Buffering, non-blocking and timeouts
Channels normally operate in blocking mode. This means that reads (gets, read, copyto) block until data is received or end-of-file is reached, or an error occurs. Similarly, writes (puts, copyto) block if the channel is not current writable.
It is possible to set a timeout for blocking reads with aio timeout,
generally useful on stream socket channels. If a timeout is specified
for a channel (the default is 0/indefinite), a blocking read will return
with no data if the timeout expires without reading any data.
For some applications, and especially when using the eventloop, blocking
I/O and timeouts are not appropriate. Instead we wish to read what is
available, and write what is possible in the readable and writable
scripts and then return until the next event. This can be achived by
setting a channel non-blocking mode with aio ndelay. In this case, aio read, aio gets
and aio puts will return early if they would otherwise block, performing
us much work as posssible. For example, aio read may return less data than requested
and aio puts may write less data than requested (although see aio flush about
additional write data can be automatically flushed). If aio gets does not receive an
entire line, it returns -1. In all these cases aio eof can be used to determine
if end-of-file was reached.
fconfigure
-
fconfigure handle ?-blocking 0|1? ?-buffering noneline|full? ?-translation mode? -
For compatibility with Tcl, a limited form of the
fconfigurecommand is supported.-
fconfigure... -blockingmaps toaiondelay -
fconfigure... -bufferingmaps toaiobuffering -
fconfigure... -translationmaps toaiotranslationand suppports onlybinaryandtext
-
eventloop: after, vwait, update
The following commands allow a script to be invoked when the given condition occurs. If no script is given, returns the current script. If the given script is the empty, the handler is removed.
-
$handle readable ?readable-script? -
Sets or returns the script for when the socket is readable.
-
$handle writable ?writable-script? -
Sets or returns the script for when the socket is writable.
-
$handle onexception ?exception-script? -
Sets or returns the script for when oob data received.
For compatibility with Tcl, these may be prefixed with fileevent. e.g.
-
fileevent $handle readable ...
Time-based execution is also available via the eventloop API.
-
after ms -
Sleeps for the given number of milliseconds. No events are processed during this time.
-
after ms|idle script ?script ...? -
The scripts are concatenated and executed after the given number of milliseconds have elapsed. If idle is specified, the script will run the next time the event loop is processed with
vwaitorupdate. The script is only run once and then removed. Returns an event id. -
after cancel id|command -
Cancels an
afterevent with the given event id or matching command (script). Returns the number of milliseconds remaining until the event would have fired. Returns the empty string if no matching event is found. -
after info ?id? -
If
idis not given, returns a list of currentafterevents. Ifidis given, returns a list containing the associated script and either timer or idle to indicated the type of the event. An error occurs ifiddoes not match an event. -
vwait ?-signal? variable ?script? -
A call to
vwaitenters the eventloop.vwaitprocesses events until the named (global) variable changes or all event handlers are removed. The variable need not exist beforehand. If there are no event handlers defined,vwaitreturns immediately. If-signalis specified,vwaitwill also quit if a handled signal occurs. In this case,signalcheck -clearcan be used to check for the signal that occurred. Ifscriptis given it is evaluated after each event. If it returns break,vwaitreturns.vwaitalso returns with an error if the script returns an error. -
update ?idletasks? -
A call to
updateenters the eventloop to process expired events, but no new events. If idletasks is specified, only expired time events are handled, not file events. Returns once handlers have been run for all expired events.
Scripts are executed at the global scope. If an error occurs during a handler script,
an attempt is made to call (the user-defined command) bgerror with the details of the error.
If the bgerror command does not exist, the error message details are printed to stderr instead.
If a file event handler script generates an error, the handler is automatically removed to prevent infinite errors. (A time event handler is always removed after execution).
-
bgerror msg -
Called when an event handler script generates an error. Note that the normal command resolution rules are used for bgerror. First the name is resolved in the current namespace, then in the global scope.
socket
Various socket types may be created as follows.
-
socket ?-noclose? unix path -
A unix domain socket client connected to path filename returns
path -
socket ?-noclose? unix.server path -
A unix domain socket server listening on path filename returns
path -
socket ?-noclose? unix.dgram ?path? -
A unix domain socket datagram client, optionally connected to path filename returns
pathif provided or "dgram" if not -
socket ?-noclose? unix.dgram.server path -
A unix domain socket datagram server server listening on path filename returns
path -
socket ?-noclose? ?-async? ?-ipv6? stream addr:port -
A TCP socket client. (See the forms for
addrbelow) filename returnsaddr:port -
socket ?-noclose? ?-async? ?-ipv6? stream.server ?addr:?port -
A TCP socket server (
addrdefaults to0.0.0.0for IPv4 or[::]for IPv6). filename returnsaddr:port -
socket ?-noclose? ?-async? ?-ipv6? dgram ?addr:port? -
A UDP socket client. If the address is not specified, the client socket will be unbound and sendto must be used to indicated the destination. filename returns
addr:portif provided or "dgram" if not -
socket ?-noclose? ?-async? ?-ipv6? dgram.server addr:port -
A UDP socket server. filename returns
addr:port -
socket ?-noclose? pipe -
A synonym for
pipefilename returns "pipe" -
socket ?-noclose? pair -
A socketpair (see socketpair(2)). Like
pipe, this command returns a list of two channels: {s1 s2}. These channels are both readable and writable. filename returns "pair" -
socket ?-noclose? pty -
A pseudo-tty pair (see openpty(3)). Like
pipe, this command returns a list of two channels: {primary replica}. These channels are both readable and writable. filename for both handles returns the replica filename.
This command creates a socket connected (client) or bound (server) to the given address.
The returned value is channel and may generally be used with the various file I/O commands (gets, puts, read, etc.), either as object-based syntax or Tcl-compatible syntax.
. set f [socket stream www.google.com:80]
aio.sockstream1
. $f puts -nonewline "GET / HTTP/1.0\r\n\r\n"
. $f gets
HTTP/1.0 302 Found
. $f closeServer sockets, however support only accept, which is most useful in conjunction with the EVENTLOOP API.
set f [socket stream.server 80]
$f readable {
set client [$f accept]
$client gets $buf
...
$client puts -nonewline "HTTP/1.1 404 Not found\r\n"
$client close
}
vwait doneThe address, addr, can be given in one of the following forms:
-
For IPv4 socket types, an IPv4 address such as 192.168.1.1
-
For IPv6 socket types, an IPv6 address such as [fe80::1234] or [::]
-
A hostname
Note that on many systems, listening on an IPv6 address such as [::] will also accept requests via IPv4.
Where a hostname is specified, the first returned address is used
which matches the socket type is used.
An unconnected dgram socket (either dgram or unix.dgram) must use
sendto to specify the destination address.
The path for Unix domain sockets is automatically removed when the socket
is closed. Use close -nodelete in the rare case where this behaviour
should be avoided (e.g. after os.fork).
If -async is specified, the socket is opened in non-blocking (ndelay) mode
and connect is non-blocking (applies to stream). In this case, a writable handler
should be used that will fire when the connect succeeds or fails, and calling peername on the handle
will succeed if connected or fail if connect failed. Typical usage is as follows:
set s [socket -async stream host:port]
$s writable {
# Remove writable either way
$s writable {}
try {
$s peername
} on error msg {
# Connect failed
incr done
return
}
$s readable {
set buf [$s read]
if {[$s eof]} {
# Closed connection
incr done
}
...
}
}
vwait doneIf -noclose is specified, the socket is not automatically closed for child proceses. e.g.
lassign [socket -noclose pipe] r w
# This file descriptor will be open in the child process
# with the file descriptors passed on the command line
exec subcommand [$r getfd] [$w getfd]syslog
syslog ?options? ?priority? message
This command sends message to system syslog facility with given priority. Valid priorities are:
emerg, alert, crit, err, error, warning, notice, info, debugIf a message is specified, but no priority is specified, then a priority of info is used.
By default, facility user is used and the value of global tcl variable argv0 is used as ident string. However, any of the following options may be specified before priority to control these parameters:
-
-facility value -
Use specified facility instead of user. The following values for facility are recognized:
authpriv, cron, daemon, kernel, lpr, mail, news, syslog, user, uucp, local0-local7 -
-ident string -
Use given string instead of argv0 variable for ident string.
-
-options integer -
Set syslog options such as
LOG_CONS,LOG_NDELAY. You should use numeric values of those from your system syslog.h file, because I haven’t got time to implement yet another hash table.
pack: pack, unpack
The optional pack extension provides commands to encode and decode binary strings.
-
pack varName value -intle|-intbe|-floatle|-floatbe|-str bitwidth ?bitoffset? -
Packs the binary representation of
valueinto the variablevarName. The value is packed according to the given type (integer/floating point/string, big-endian/little-endian), width and bit offset. The variable is created if necessary (likeappend). The variable is expanded if necessary. -
unpack binvalue -intbe|-intle|-uintbe|-uintle|-floatbe|-floatle|-str bitpos bitwidth -
Unpacks bits from
binvalueat bit positionbitposand withbitwidth. Interprets the value according to the type (integer/floating point/string, big-endian/little-endian and signed/unsigned) and returns it. For integer types,bitwidthmay be up to the size of a Jim Tcl integer (typically 64 bits). For floating point types,bitwidthmay be 32 bits (for single precision numbers) or 64 bits (for double precision). For the string type, both the width and the offset must be on a byte boundary (multiple of 8). Attempting to access outside the length of the value will return 0 for integer types, 0.0 for floating point types or the empty string for the string type.
zlib
The optional zlib extension provides a Tcl-compatible subset of the zlib command.
-
crc32 data ?startValue? -
Returns the CRC32 checksum of a buffer. Optionally, an initial value may be specified; this is most useful for calculating the checksum of chunked data read from a stream (for instance, a pipe).
-
deflate string ?level? -
Compresses a buffer and outputs a raw, Deflate-compressed stream. Optionally, a compression level (1-9) may be specified to choose the desired speed vs. compression rate ratio.
-
inflate data ?bufferSize? -
Decompresses a raw, Deflate-compressed stream. When the uncompressed data size is known and specified, memory allocation is more efficient. Otherwise, decompression is chunked and therefore slower.
-
gzip string ?-level level? -
Compresses a buffer and adds a gzip header.
-
gunzip data ?-buffersize size? -
Decompresses a gzip-compressed buffer. Decompression is chunked, with a default, small buffer size of 64K which guarantees lower memory footprint at the cost of speed. It is recommended to use a bigger size, on systems without a severe memory constraint.
binary
The optional, pure-Tcl binary extension provides the Tcl-compatible binary scan and binary format
commands based on the low-level pack and unpack commands.
See the Tcl documentation at: http://www.tcl.tk/man/tcl8.5/TclCmd/binary.htm
Note that binary format with f/r/R specifiers (single-precision float) uses the value of Infinity in case of overflow.
oo: class, super
The optional, pure-Tcl oo extension provides object-oriented (OO) support for Jim Tcl.
See the online documentation (http://jim.tcl.tk/index.html/doc/www/www/documentation/oo/) for more details.
-
class classname ?baseclasses? classvars -
Create a new class,
classname, with the given dictionary (classvars) as class variables. These are the initial variables which all newly created objects of this class are initialised with. If a list of baseclasses is given, methods and instance variables are inherited. -
super method ?args ...? -
From within a method, invokes the given method on the base class. Note that this will only call the last baseclass given.
tree
The optional, pure-Tcl tree extension implements an OO, general purpose tree structure similar to that provided by tcllib ::struct::tree (http://core.tcl.tk/tcllib/doc/trunk/embedded/www/tcllib/files/modules/struct/struct_tree.html)
A tree is a collection of nodes, where each node (except the root node) has a single parent and zero or more child nodes (ordered), as well as zero or more attribute/value pairs.
-
tree -
Creates and returns a new tree object with a single node named "root". All operations on the tree are invoked through this object.
-
$tree destroy -
Destroy the tree and all it’s nodes. (Note that the tree will also be automatically garbage collected once it goes out of scope).
-
$tree set nodename key value -
Set the value for the given attribute key.
-
$tree lappend nodename key value ... -
Append to the (list) value(s) for the given attribute key, or set if not yet set.
-
$tree keyexists nodename key -
Returns 1 if the given attribute key exists.
-
$tree get nodename key -
Returns the value associated with the given attribute key.
-
$tree getall nodename -
Returns the entire attribute dictionary associated with the given key.
-
$tree depth nodename -
Returns the depth of the given node. The depth of "root" is 0.
-
$tree parent nodename -
Returns the node name of the parent node, or "" for the root node.
-
$tree numchildren nodename -
Returns the number of child nodes.
-
$tree children nodename -
Returns a list of the child nodes.
-
$tree next nodename -
Returns the next sibling node, or "" if none.
-
$tree insert nodename ?index? -
Add a new child node to the given node. The index is a list index such as
3orend-2. The default index isend. Returns the name of the newly added node. -
$tree walk nodename dfs|bfs {actionvar nodevar} script -
Walks the tree starting from the given node, either breadth first (
bfs) depth first (dfs). The value"enter"or"exit"is stored in variableactionvar. The name of each node is stored innodevar. The script is evaluated twice for each node, on entry and exit. -
$tree dump -
Dumps the tree contents to stdout
tcl::prefix
The optional tclprefix extension provides the Tcl8.6-compatible tcl::prefix command
(http://www.tcl.tk/man/tcl8.6/TclCmd/prefix.htm) for matching strings against a table
of possible values (typically commands or options).
-
tcl::prefix all table string -
Returns a list of all elements in
tablethat begin with the prefixstring. -
tcl::prefix longest table string -
Returns the longest common prefix of all elements in
tablethat begin with the prefixstring. -
tcl::prefix match ?options? table string -
If
stringequals one element intableor is a prefix to exactly one element, the matched element is returned. If not, the result depends on the-erroroption.-
-exactAccept only exact matches. -
-message stringUsestringin the error message at a mismatch. Default is "option". -
-error optionsThe options are used when no match is found. Ifoptionsis empty, no error is generated and an empty string is returned. Otherwise the options are used as return options when generating the error message. The default corresponds to setting-level 0.
-
tcl::autocomplete
Scriptable command line completion is supported in the interactive shell, jimsh, through
the tcl::autocomplete callback. A simple implementation is provided, however this may
be replaced with a custom command instead if desired.
In the interactive shell, press <TAB> to activate command line completion.
-
tcl::autocomplete commandline -
This command is called with the current command line when the user presses <TAB>. The command should return a list of all possible command lines that match the current command line. For example if
pris the current command line, the list{prefix proc}may be returned.
tcl::stdhint
Scriptable hinting is supported in the interactive shell, jimsh, through
the tcl::stdhint callback. A simple implementation is provided, however this may
be replaced with a custom command instead if desired.
In the interactive shell, press <TAB> to activate command line completion.
-
tcl::stdhint commandline -
This command is called with the current command line. It should return a list of
{hint ?ANSI cols?}or "" if no hint is available. For example, if passed"dict get"it could return{"dict get dictionary ?key …?" 36 1}to show the given hint in light cyan.
The built-in tcl::stdhint callback uses tcl::stdhint_col for the colour. tcl::stdhint_cols can be used
to easily change this colour, e.g. in ~/.jimrc.
. parray tcl::stdhint_cols
tcl::stdhint_cols(black) = 30
tcl::stdhint_cols(blue) = 34
tcl::stdhint_cols(cyan) = 36
tcl::stdhint_cols(gray) = 30 1
tcl::stdhint_cols(green) = 32
tcl::stdhint_cols(grey) = 30 1
tcl::stdhint_cols(lblue) = 34 1
tcl::stdhint_cols(lcyan) = 36 1
tcl::stdhint_cols(lgreen) = 32 1
tcl::stdhint_cols(lpurple) = 35 1
tcl::stdhint_cols(lred) = 31 1
tcl::stdhint_cols(lyellow) = 33 1
tcl::stdhint_cols(none) = 0
tcl::stdhint_cols(normal) = 37
tcl::stdhint_cols(purple) = 35
tcl::stdhint_cols(red) = 31
tcl::stdhint_cols(white) = 37 1
tcl::stdhint_cols(yellow) = 33history
The optional history extension provides script access to the command line editing
and history support available in jimsh. See examples/jtclsh.tcl for an example.
Note: if line editing support is not available, history getline acts like gets and
the remaining subcommands do nothing.
-
history load filename -
Load history from a (text) file. If the file does not exist or is not readable, it is ignored.
-
history getline prompt ?varname? -
Displays the given prompt and allows a line to be entered. Similarly to
gets, ifvarnameis given, it receives the line and the length of the line is returned, or -1 on EOF. Ifvarnameis not given, the line is returned directly. -
history completion command -
Sets an autocompletion command (see
tcl::autocomplete) that is active duringhistorygetline. If the command is empty, autocompletion is disabled. -
history hints command -
Sets a hinting command (see
tcl::stdhint) that is active duringhistorygetline. If the command is empty, hinting is disabled. -
history add line -
Adds the given line to the history buffer.
-
history keep ?count? -
Set or return the maximum history size. Defaults to 100.
-
history save filename -
Saves the current history buffer to the given file.
-
history show -
Displays the current history buffer to standard output.
namespace
Provides namespace-related functions. See also: http://www.tcl.tk/man/tcl8.6/TclCmd/namespace.htm
-
namespace canonical ?current? ?name? -
Returns the full name of
namewithin namespacecurrent. Ifcurrentis not given,namespacecurrentis used. If neither are given, returns the current namespace (not qualified with a leading ::). -
namespace code script -
Captures the current namespace context for later execution of the script
script. It returns a new script in which script has been wrapped in anamespace inscopecommand. -
namespace current -
Returns the fully-qualified name for the current namespace.
-
namespace delete ?namespace …? -
Deletes all commands and variables with the given namespace prefixes.
-
namespace ensemble create -
Creates an ensemble command for the current namespace (requires the ensemble extension').
-
namespace eval namespace arg ?arg…? -
Activates a namespace called
namespaceand evaluates some code in that context. -
namespace origin command -
Returns the fully-qualified name of the original command to which the imported command
commandrefers. -
namespace parent ?namespace? -
Returns the fully-qualified name of the parent namespace for namespace
namespace, if given, otherwise for the current namespace. -
namespace qualifiers string -
Returns any leading namespace qualifiers for
string -
namespace tail string -
Returns the simple name at the end of a qualified string.
-
namespace upvar namespace ?arg…? -
This command arranges for zero or more local variables in the current procedure to refer to variables in
namespace -
namespace which ?-command|-variable? name -
Looks up
nameas either a command (the default) or variable and returns its fully-qualified name.
interp
The optional interp command allows sub-interpreters to be created where commands may be run independently (but synchronously) of the main interpreter.
-
interp -
Creates and returns a new interpreter object (command). The created interpreter contains any built-in commands along with static extensions, but does not include any dynamically loaded commands (package require, load). These must be reloaded in the child interpreter if required.
-
$interp delete -
Deletes the interpreter object.
-
$interp eval script … -
Evaluates a script in the context for the child interpreter, in the same way as eval.
-
$interp alias alias childcmd parentcmd ?arg …? -
Similar to alias, but creates a command,
childcmd, in the child interpreter that is an alias forparentcmdin the parent interpreter, with the given, fixed arguments. The alias may be deleted in the child with rename.
json::encode
The Tcl → JSON encoder is part of the optional json package.
-
json::encode value ?schema? -
Encode a Tcl value as JSON according to the schema (defaults to
str). The following schema types are supported:-
str - Tcl string → JSON string
-
num - Tcl value → bare numeric value or null
-
bool - Tcl boolean value → true, false
-
obj ?name subschema …? - Tcl dict → JSON object. For each dict key matching name, the corresponding subschema is applied. The special name
*matches any keys not otherwise matched, otherwise the defaultstris used. -
list ?subschema? - Tcl list → JSON array. The subschema (default
str) is applied for each element of the list/array. -
mixed ?subschema …? = Tcl list → JSON array. Each subschema is applied for the corresponding element of the list/array.
-
-
The following are examples:
. json::encode {1 2 true false null 5.0} list
[ "1", "2", "true", "false", "null", "5.0" ]
. json::encode {1 2 true false null 5.0} {list num}
[ 1, 2, true, false, null, 5.0 ]
. json::encode {0 1 2 true false 5.0 off} {list bool}
[ false, true, true, true, false, true, false ]
. json::encode {a 1 b hello c {3 4}} obj
{ "a":"1", "b":"hello", "c":"3 4" }
. json::encode {a 1 b hello c {3 4}} {obj a num c {list num}}
{ "a":1, "b":"hello", "c":[ 3, 4 ] }
. json::encode {true true {abc def}} {mixed str num obj}
[ "true", true, { "abc":"def" } ]
. json::encode {a 1 b 3.0 c hello d null} {obj c str * num}
{ "a":1, "b":3.0, "c":"hello", "d":null }json::decode
The JSON → Tcl decoder is part of the optional json package.
-
json::decode ?-index? ?-null string? ?-schema? json-string -
Decodes the given JSON string (must be array or object) into a Tcl data structure. If
-indexis specified, decodes JSON arrays as dictionaries with numeric keys. This makes it possible to retrieve data from nested arrays and dictionaries with justdict get. With the option-schemareturns a list of{data schema}where the schema is compatible withjson::encode. Otherwise just returns the data. Decoding is as follows (with schema types listed in parentheses):-
object → dict (obj)
-
array → list (mixed or list)
-
number → as-is (num)
-
boolean → as-is (bool)
-
string → string (str)
-
null → supplied null string or the default
"null"(num)
-
-
Note that an object decoded into a dict will return the keys in the same order as the original string.
. json::decode {[1, 2]}
{1 2}
. json::decode -schema {[1, 2]}
{1 2} {list num}
. json::decode -schema {{"a":1, "b":2}}
{a 1 b 2} {obj a num b num}
. json::decode -schema {[1, 2, {a:"b", c:false}, "hello"]}
{1 2 {a b c false} hello} {mixed num num {obj a str c bool} str}
. json::decode -index {["foo", "bar"]}
{0 foo 1 bar}BUILT-IN VARIABLES
The following global variables are created automatically by the Tcl library.
-
env -
This variable is set by Jim as an array whose elements are the environment variables for the process. Reading an element will return the value of the corresponding environment variable. This array is initialised at startup from the
envcommand. It may be modified and will affect the environment passed to commands invoked withexec. -
platform_tcl -
This variable is set by Jim as an array containing information about the platform on which Jim was built. Currently this includes os and platform.
-
auto_path -
This variable contains a list of paths to search for packages. It defaults to a location based on where jim is installed (e.g.
/usr/local/lib/jim), but may be changed byjimshor the embedding application. Note thatjimshwill consider the environment variable$JIMLIBto be a list of colon-separated list of paths to add toauto_path. -
errorCode -
This variable holds the value of the -errorcode return option set by the most recent error that occurred in this interpreter. This list value represents additional information about the error in a form that is easy to process with programs. The first element of the list identifies a general class of errors, and determines the format of the rest of the list. The following formats for -errorcode return options are used by the Tcl core; individual applications may define additional formats. Currently only
execsets this variable. Otherwise it will beNONE.
The following global variables are set by jimsh.
-
tcl_interactive -
This variable is set to 1 if jimsh is started in interactive mode or 0 otherwise.
-
tcl_platform -
This variable is set by Jim as an array containing information about the platform upon which Jim was built. The following is an example of the contents of this array.
tcl_platform(bootstrap) = 0
tcl_platform(byteOrder) = littleEndian
tcl_platform(engine) = Jim
tcl_platform(os) = darwin
tcl_platform(pathSeparator) = :
tcl_platform(platform) = unix
tcl_platform(pointerSize) = 8
tcl_platform(stackFormat) = 4
tcl_platform(threaded) = 0
tcl_platform(wordSize) = 8-
argv0 -
If jimsh is invoked to run a script, this variable contains the name of the script.
-
argv -
If jimsh is invoked to run a script, this variable contains a list of any arguments supplied to the script.
-
argc -
If jimsh is invoked to run a script, this variable contains the number of arguments supplied to the script.
-
jim::argv0 -
The value of argv[0] when jimsh was invoked.
-
jim::lineedit -
This variables is set to 1 if jimsh was configured with line editing support, or 0 if not.
The following variables have special meaning to Jim Tcl:
-
jim::defer -
If this variable is set, it is considered to be a list of scripts to evaluate when the current proc exits (local variables), or the interpreter exits (global variable). See
defer. -
history::multiline -
If this variable is set to "1", interactive line editing operates in multiline mode. That is, long lines will wrap across multiple lines rather than scrolling within a single line.
CHANGES IN PREVIOUS RELEASES
In v0.74
In v0.73
-
Built-in regexp now support non-capturing parentheses: (?:…)
-
Add
stringreplace -
Add
stringtotitle -
Add
infostatics -
Add
build-jim-extfor easy separate building of loadable modules (extensions) -
localnow works with any command, not just procs -
Add
infoaliasto access the target of an alias -
UTF-8 encoding past the basic multilingual plane (BMP) is supported
-
Add
tcl::prefix -
Add
history -
Most extensions are now enabled by default
-
Add support for namespaces and the
namespacecommand -
Add
apply
In v0.72
-
procs now allow args and optional parameters in any position
-
Add Tcl-compatible expr functions,
rand(),srand()andpow() -
Add support for the -force option to
filedelete -
Better diagnostics when
sourcefails to load a script with a missing quote or bracket -
New
tcl_platform(pathSeparator) -
Add support settings the modification time with
filemtime -
execis now fully supported on win32 (mingw32) -
Line editing is now supported for the win32 console (mingw32)
-
Add
aiolistencommand
In v0.71
-
Allow args to be renamed in procs
-
Add
$(…)shorthand syntax for expressions -
Add automatic reference variables in procs with
&varsyntax -
Support
jimsh --version -
Additional variables in
tcl_platform() -
localprocs now push existing commands andupcallcan call them -
Add
loopcommand (TclX compatible) -
Add
aiobufferingcommand -
infocompletecan now return the missing character -
binaryformatandbinaryscanare now (optionally) supported -
Add
stringbyterange -
Built-in regexp now support non-greedy repetition (*?, +?, ??)
In v0.70
-
platform_tcl()settings are now automatically determined -
Add aio
$handle filename -
Add
infochannels -
The bio extension is gone. Now
aiosupports copyto. -
Add
existscommand -
Add the pure-Tcl oo extension
-
The
execcommand now only uses vfork(), not fork() -
Unit test framework is less verbose and more Tcl-compatible
-
Optional UTF-8 support
-
Optional built-in regexp engine for better Tcl compatibility and UTF-8 support
-
Command line editing in interactive mode, e.g. jimsh
In v0.63
-
sourcenow checks that a script is complete (.i.e. not missing a brace) -
info complete now uses the real parser and so is 100% accurate
-
Better access to live stack frames with info frame,
stacktraceandstackdump -
tailcallno longer loses stack trace information -
lambda,aliasandcurryare implemented viatailcallfor efficiency -
localallows procedures to be deleted automatically at the end of the current procedure -
udp sockets are now supported for both clients and servers.
-
vfork-based exec is now working correctly
-
Add file tempfile
-
Add socket pipe
-
Enhance try … on … finally to be more Tcl 8.6 compatible
-
IPv6 support is now included
-
Add string is
-
Event handlers works better if an error occurs. eof handler has been removed.
-
execnow sets $::errorCode, and catch sets opts(-errorcode) for exit status -
Command pipelines via open "|…" are now supported
-
pidcan now return pids of a command pipeline -
Add info references
-
Add support for after
'ms, 'after idle, after info,update -
execnow sets environment based on $::env -
Add dict keys
-
Add support for lsort -index
In v0.62
-
Add support to
execfor >&, >>&, |&, 2>@1 -
Fix
execerror messages when special token (e.g. >) is the last token -
Fix
substhandling of backslash escapes. -
Allow abbreviated options for
subst -
Many
exprbug fixes -
Add support for functions in
expr(e.g. int(), abs()), and also in, ni list operations -
The variable name argument to
regsubis now optional -
Add support for unset -nocomplain
-
Fully-functional
lsearchis now implemented -
Add info nameofexecutable and info returncodes
-
Allow
catchto determine what return codes are caught -
Allow
incrto increment an unset variable by first setting to 0 -
Allow args and optional arguments to the left or required arguments in
proc -
Add file copy
-
Add try … finally command
LICENCE
Copyright 2005 Salvatore Sanfilippo <antirez@invece.org>
Copyright 2005 Clemens Hintze <c.hintze@gmx.net>
Copyright 2005 patthoyts - Pat Thoyts <patthoyts@users.sf.net>
Copyright 2008 oharboe - Oyvind Harboe - oyvind.harboe@zylin.com
Copyright 2008 Andrew Lunn <andrew@lunn.ch>
Copyright 2008 Duane Ellis <openocd@duaneellis.com>
Copyright 2008 Uwe Klein <uklein@klein-messgeraete.de>
Copyright 2009 Steve Bennett <steveb@workware.net.au>Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following
disclaimer in the documentation and/or other materials
provided with the distribution.THIS SOFTWARE IS PROVIDED BY THE JIM TCL PROJECT ``AS IS'' AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
JIM TCL PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.The views and conclusions contained in the software and documentation
are those of the authors and should not be interpreted as representing
official policies, either expressed or implied, of the Jim Tcl Project.