Jim Tcl(n)

SYNOPSIS

cc <source> -ljim

jimsh <script>

Quick Index

+
+Command Reference +
+
+
+Operator Precedence +
+
+
+Builtin Variables +
+
+
+Backslash Sequences +
+

INTRODUCTION

Jim is a reimplementation of Tcl, combining some features from +earlier, smaller versions of Tcl (6.x) as well as more modern +features from later versions of Tcl (7.x, 8.x). It also has some some +entirely new features not available in any version of Tcl.

This version is approximately the same size as "tinytcl" (6.8) but +is faster and has more features.

Note that most of this man page is the original 6.8 Tcl man page, with +changes made for differences with Jim.

The major differences are:

+
+Object-based I/O (aio) with backward compatibility wrapper +
+
+
+I/O: Support for sockets (client and server) +
+
+
+I/O: Support for readable/writable event handlers +
+
+
+Integers are 64bit +
+
+
+Support for references (ref/getref/setref) and garbage collection +
+
+
+Builtin dictionary type (dict) +
+
+
+file mkdir, file rename, file tempfile (Tcl 7.x, 8.x) +
+
+
+env command to access environment variables +
+
+
+List: lmap, lset, lreverse, lassign (Tcl 8.x) +
+
+
+os.fork, os.wait, rand +
+
+
+{*}/{expand} +
+
+
+string map (Tcl 7.x) +
+
+
+subst (Tcl 7.x) +
+
+
+switch (Tcl 7.x) (note that case is provided for compatibility) +
+
+
+Much better error reporting. info stacktrace as a replacement for errorInfo, errorCode +
+
+
+Support for "static" variables in procedures +
+
+
+Significantly faster for many scripts/operations +
+
+
+Support for tail-call optimisation, tailcall +
+
+
+Variable traces are not supported +
+
+
+The history command is not supported +
+

CHANGES

Since v0.62:

+
+source now 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, stacktrace and stackdump +
+
+
+tailcall no longer loses stack trace information +
+
+
+Add alias and curry +
+
+
+lambda, alias and curry are implemented via tailcall for efficiency +
+
+
+local allows 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 +
+
+
+It is now possible to return from within try +
+
+
+IPv6 support is now included +
+
+
+Add string is +
+
+
+Event handlers works better if an error occurs. eof handler has been removed. +
+
+
+exec now sets $::errorCode, and catch sets opts(-errorcode) for exit status +
+
+
+Command pipelines via open "|…" are now supported +
+
+
+pid can now return pids of a command pipeline +
+
+
+Add info references +
+
+
+Add support for after ms, after idle, after info, update +
+
+
+exec now sets environment based on $::env +
+

Since v0.61:

+
+Add support to exec for >&, >>&, |&, 2>@1 +
+
+
+Fix exec error messages when special token (e.g. >) is the last token +
+
+
+Fix subst handling of backslash escapes. +
+
+
+Allow abbreviated options for subst +
+
+
+Add support for return, break, continue in subst +
+
+
+Many expr bug fixes +
+
+
+Add support for functions in expr (e.g. int(), abs()), and also in, ni list operations +
+
+
+The variable name argument to regsub is now optional +
+
+
+Add support for unset -nocomplain +
+
+
+Add support for list commands: lassign, lrepeat +
+
+
+Fully-functional lsearch is now implemented +
+
+
+Add info nameofexecutable and info returncodes +
+
+
+Allow catch to determine what return codes are caught +
+
+
+Allow incr to 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 +
+

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.

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.

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 behavior 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 22

has 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_CreateCommand, 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 foo

Brackets 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.gorp

A 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]x

is equivalent to the command

set a x24x

If 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.c

is equivalent to the command

set a test.c

There 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)zyx

is equivalent to the command

set a xyz87zyx

If the variable index has the value 14, then the command

set a xyz$x($index)zyx

is equivalent to the command

set a xyzmorezyx

For more information on arrays, see VARIABLES 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}bar

is equivalent to the command

set a abctestbar

Variable 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). +
+
+\{ +: +
+ Left brace ({). +
+
+\} +: +
+ Right brace (}). +
+
+\[ +: +
+ Open bracket ([). +
+
+\] +: +
+ Close bracket (]). +
+
+\$ +: +
+ Dollar sign ($). +
+
+\<space> +: +
+ Space ( ): doesn’t terminate argument. +
+
+\; +: +
+ Semi-colon: doesn’t terminate command. +
+
+\" +: +
+ Double-quote. +
+
+\<newline> +: +
+ Nothing: this joins two lines together + into a single line. This backslash feature is unique in that + it will be applied even when the sequence occurs within braces. +
+
+\\ +: +
+ Backslash (\). +
+
+\ddd +: +
+ The digits ddd (one, two, or three of them) give the octal value of + the character. Note that Jim supports null characters in strings. +
+

For example, in the command

set a \{x\[\ yz\141

the second argument to set will be {x[ yza.

If a backslash is followed by something other than one of the options +described above, then the backslash is transmitted to the argument +field without any special processing, and the Tcl scanner continues +normal processing with the next character. For example, in the +command

set \*a \\\{foo

The first argument to set will be \*a and the second +argument will be \{foo.

If an argument is enclosed in braces, then backslash sequences inside +the argument are parsed but no substitution occurs (except for +backslash-newline): 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 0 refers to the first element of the string + or list. +
+
+integer+integer or +
+integer-integer +: +
+ The sum or difference of the two integers. e.g. 2+3 refers to the 5th element. + This is useful when used with (e.g.) $i+1 rather than the more verbose + [expr {$i+1}] +
+
+end +: +
+ The last element of the string or list. +
+
+end-integer +: +
+ The nth-from-last element of the string or list. +
+

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 + 6

evaluates 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.

Integer values may be specified in decimal (the normal case), in octal (if the +first character of the operand is 0), or in hexadecimal (if the first +two characters of the operand are 0x).

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).

+
+Operands may be specified in any of the following ways: +
+
+
+As a numeric value, either integer or floating-point. +
+
+
+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"  0

The valid operators are listed below, grouped in decreasing order +of precedence:

+int() double() round() abs() +: +
+ Unary functions. + 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. +
+
+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. +
+
+** +: +
+ Power. e.g. pow(). If Jim is compiled with math support, supports doubles and + integers. Otherwise supports integers only. +
+
+* / % +: +
+ 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. +
+
+< > \<= >= +: +
+ 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. +
+
+== != +: +
+ 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. +
+
+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 x + evaluates to non-zero, then the result is the value of y. + Otherwise the result is the value of z. + The x operand must have a numeric value, while y and z can + 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 < 7

evaluates 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 behavior 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, +and 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 / 4

yields 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 + $b

results 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 for’s second argument 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 John

is 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).

The Tcl commands concat, foreach, lappend, lindex, linsert, +list, llength, lrange, lreplace, lsearch, and lsort allow +you to build lists, extract elements from them, search them, and perform +other list-related functions.

Advanced list commands include lrepeat, lreverse, lmap, lassign, lset.

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 $cmd

This will attempt to exec the 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 {*}$cmd

This 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

Tcl provides two commands that support string matching using +egrep-style regular expressions: regexp and regsub.

Regular expressions are implemented using the system’s C library as +Extended Regular Expressions (EREs) rather than Basic Regular Expressions (BREs).

See regex(3) and regex(7) for full details.

NOTE Tcl 7.x and 8.x use perl-style Advanced Regular Expressions (AREs).

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 return command has been invoked, and that the + current procedure (or top-level command or source command) + should return immediately. The + string gives the return value for the procedure or command. +
+
+JIM_BREAK(3) +: +
+ Indicates that the break command has been invoked, so the + innermost loop should abort immediately. The string should always + be empty. +
+
+JIM_CONTINUE(4) +: +
+ Indicates that the continue command 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 signal and catch commands. +
+
+JIM_EXIT(6) +: +
+ Indicates that the command called the exit command. + The string contains the exit code. +
+

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 args ?statics? body

The new command is name 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.

args 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. +
+
+args +: +
+ Variable Argument - The special name args, which is + assigned all remaining arguments (including none). The + variable argument may only be specified once. +
+

Arguments must be provided in the following order, any of which +may be omitted:

+
+Required Arguments (Left) +
+
+
+Optional Arguments +
+
+
+Variable Argument +
+
+
+Required Arguments (Right) +
+

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 follows:

+
+Left Required Arguments are assigned from the left +
+
+
+Right Required Arguments are assigned from the right +
+
+
+Default Arguments are assigned from the left, following the Left Required Arguments. +
+
+
+A list is formed from any remaining arguments, which are then + are assigned to the args Variable Argument (if specified). The list will be empty + if there are no remaining arguments. +
+

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:

jim> set a 1
+jim> proc a {} {a {b 2}} {
+    set c 1
+    puts "$a $b $c"
+    incr a
+    incr b
+    incr c
+}
+jim> a
+1 2 1
+jim> a
+2 3 1

The 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.

See the proc command for information on +how to define procedures and what happens when they are invoked.

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) 44

will 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) 2

set 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"
+}
+p

will output:

1 2 3

ARRAYS 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:

two

Thus array set is equivalent to set when the variable does not +exist or is empty.

The reverse is also true where an array will be converted into +a list.

set a(1) one; set a(2) two
+puts $a

will output:

1 one 2 two

DICTIONARY 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.

jim> dict set a 1 one
+1 one
+jim> dict set a 2 two
+1 one 2 two
+jim> puts $a
+1 one 2 two
+jim> puts $a(2)
+two
+jim> dict set a 3 T three
+1 one 2 two 3 {T three}

See the dict command for more details.

GARBAGE COLLECTION, REFERENCES, LAMBDA

Unlike Tcl, Jim has some sophistocated 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:

jim> set r [ref "One String" test]
+<reference.<test___>.00000000000000000000>
+jim> getref $r
+One String

The operation ref creates a references to the value specfied 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.

jim> setref $r "New String"
+New String
+jim> getref $r
+New String

The 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:

jim> proc f {ref value} { puts "Finaliser called for $ref,$value" }
+jim> set r [ref "One String" test f]
+<reference.<test___>.00000000000
+jim> collect
+0
+jim> set r ""
+jim> collect
+Finaliser called for <reference.<test___>.00000000000,One String
+1

Note 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

jim> finalize $r
+f
+jim> finalize $r newf
+newf

Lambda

Jim provides a garbage collected lambda function. This is a procedure +which is able to create an anonymous procedure. Consider:

jim> set f [lambda {a} {{x 0}} { incr x $a }]
+jim> $f 1
+1
+jim> $f 2
+3
+jim> 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.

jim> rename $f ""

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 ularm(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 (proc) for one or more words. For example, +the following creates an alias for the command info exists.

alias e info exists
+if {[e var]} {
+  ...
+}

alias returns name, allowing it to be used with 'local.

See also proc, curry, lambda, local.

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.

This command provides an efficient way to build up long +variables incrementally. +For example, append a $b is much more efficient than +set a $a$b if $a is long.

array

array option arrayName ?arg 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 arrayName is an array variable, 0 if there is + no variable by that name. This command is essentially + identical to info exists +
+
+array get arrayName ?pattern? +: +
+ Returns a list containing pairs of elements. The first + element in each pair is the name of an element in arrayName + and the second element of each pair is the value of the + array element. The order of the pairs is undefined. If + pattern is not specified, then all of the elements of the + array are included in the result. If pattern is specified, + then only those elements whose names match pattern (using + the matching rules of string match) are included. If arrayName + isn’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. If pattern is omitted then + the command returns all of the element names in the array. + If pattern is specified, then only those elements whose + names match pattern (using the matching rules of string + match) are included. If there are no (matching) elements + in the array, or if arrayName isn’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. list + must 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 variable arrayName does not + already exist and list is empty, arrayName is created with + an empty array value. +
+
+array size arrayName +: +
+ Returns the number of elements in the array. If arrayName + isn’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 the matching rules of string match). If arrayName + isn’t the name of an array variable or there are no matching + elements in the array, no error will be raised. If pattern + is omitted and arrayName is an array variable, then the + command unsets the entire array. The command always returns + an empty string. +
+

break

break

This command may be invoked only inside the body of a loop command +such as for or foreach or while. It returns a JIM_BREAK code +to signal the innermost containing loop command to return immediately.

case

case string ?in? patList body ?patList body …?

case string ?in? {patList body ?patList body …?}

Note that the switch command should generally be preferred unless compatibility +with Tcl 6.x is desired.

Match string against each of the patList arguments +in order. If one matches, then evaluate the following body argument +by passing it recursively to the Tcl interpreter, and return the result +of that evaluation. Each patList argument consists of a single +pattern or list of patterns. Each pattern may contain any of the wild-cards +described under string match.

If a patList argument is default, the corresponding body will be +evaluated if no patList matches string. If no patList argument +matches string and no default is given, then the case command returns +an empty string.

Two syntaxes are provided.

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 case commands, +since the braces around the whole list make it unnecessary to include a +backslash at the end of each line.

Since the patList arguments are in braces in the second form, +no command or variable substitutions are performed on them; this makes +the behavior of the second form different than the first form in some +cases.

Below are some examples of case commands:

case abc in {a b} {format 1} default {format 2} a* {format 3}

will return 3,

case a in {
+    {a b} {format 1}
+    default {format 2}
+    a* {format 3}
+}

will return 1, and

case xyz {
+    {a b}
+        {format 1}
+    default
+        {format 2}
+    a*
+        {format 3}
+}

will return 2.

catch

catch ?-?no?code …? ?--? command ?resultVarName? ?optionsVarName?

The catch command may be used to prevent errors from aborting +command interpretation. Catch evalues 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.

Note that if a signal marked as signal handle is caught with catch -signal, the return value +(stored in resultVarName) is name of the signal caught.

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 format seconds ?-format format? +: +
+ 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. +
+
+clock scan str -format format +: +
+ Scan the given time string using the given format string. + See strptime(3) for supported formats. +
+

close

close fileId

fileId close

Closes the file given by fileId. +fileId must be the return value from a previous invocation +of the open command; after this command, it should not be +used anymore.

collect

collect

Normally reference garbage collection is automatically performed periodically. +However it may be run immediately with the collect command.

See GARBAGE COLLECTION, REFERENCES, LAMBDA 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

This command may be invoked only inside the body of a loop command such +as for or foreach or while. 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.

curry

alias 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.

See also proc, alias, lambda, local.

dict

dict option ?arg 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 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 dict get + on that path will succeed. +
+
+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 dict get $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 man- ner 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 set dictionaryName key ?key …? value+ +: +
+ This operation takes the name of 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 unset dictionaryName key ?key …? value+ +: +
+ This operation (the companion to dict set) 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. +
+

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 …}

eof

eof fileId

fileId eof

Returns 1 if an end-of-file condition has occurred on fileId, +0 otherwise.

fileId must have been the return value from a previous call to open, +or it may be stdin, stdout, or stderr to refer to one of the +standard I/O channels.

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]

See also errorInfo, info stacktrace, catch and return

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
+}

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 …?

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.

If any of the commands in the pipeline exit abnormally or +are killed or suspended, then exec will return an error +and the error message will include the pipeline’s output followed by +error messages describing the abnormal terminations.

If any of the commands writes to its standard error file, +then exec will return an error, and the error message +will include the pipeline’s output, followed by messages +about abnormal terminations (if any), followed by the standard error +output.

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 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 exec + will 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 situation exec + will normally return an empty string. +
+
+2>filename +: +
+ The standard error of the last command in the pipeline + is redirected to the file. +
+
+2>>filename +: +
+ As above, but append to the file. +
+
+2>@fileId +: +
+ The standard error of the last command in the pipeline is + redirected to the given (writable) file descriptor. +
+
+2>@1 +: +
+ The standard error of the last command in the pipeline is + redirected to the same file descriptor as the standard output. +
+
+>&filename +: +
+ Both the standard output and standard error of the last command + in the pipeline is 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. +
+

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 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 >.

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).

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.

file

file option name ?arg 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 name + was 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 source to file target. The source file must exist. + The target file must not exist, unless -force is specified. +
+
+file delete 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. +
+
+file dirname name +: +
+ Return all of the characters in name up to but not including + the last slash character. If there are no slashes in name + then return . (a single dot). If the last slash in name is its first + character, then return /. +
+
+file executable name +: +
+ Return 1 if file name is executable by + the current user, 0 otherwise. +
+
+file exists name +: +
+ Return 1 if file name exists and the current user has + search privileges for the directories leading to it, 0 otherwise. +
+
+file extension name +: +
+ Return all of the characters in name after and including the + last dot in name. If there is no dot in name then return + the empty string. +
+
+file isdirectory name +: +
+ Return 1 if file name is a directory, + 0 otherwise. +
+
+file isfile name +: +
+ Return 1 if file name is a regular file, + 0 otherwise. +
+
+file join arg arg … +: +
+ Joins multiple path components. Note that if any components is + an absolute path, the preceding components are ignored. + Thus file join /tmp /root returns /root. +
+
+file lstat name varName +: +
+ Same as stat option (see below) except uses the lstat + kernel call instead of stat. This means that if name + refers to a symbolic link the information returned in varName + is 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 dir specified, + this command will create all non-existing parent directories + as well as dir itself. 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 +: +
+ Return a decimal string giving the time at which file name + was 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. +
+
+file normalize name +: +
+ Return the normalized path of name. See realpath(3). +
+
+file owned name +: +
+ Return 1 if file name is owned by the current user, + 0 otherwise. +
+
+file readable name +: +
+ Return 1 if file name is 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). If + name isn’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 oldname newname +: +
+ Renames the file from the old name to the new name. +
+
+file rootname name +: +
+ Return all of the characters in name up to but not including + the last . character in the name. If name doesn’t contain + a dot, then return name. +
+
+file size name +: +
+ Return a decimal string giving the size of file name in bytes. + If the file doesn’t exist or its size cannot be queried then an + error is generated. +
+
+file stat name varName +: +
+ Invoke the stat kernel call on name, and use the + variable given by varName to hold information returned from + the kernel call. + VarName is treated as an array variable, + and the following elements of that variable are set: atime, + ctime, dev, gid, ino, mode, mtime, + nlink, size, type, uid. + 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 command file type. + This command returns an empty string. +
+
+file tail name +: +
+ Return all of the characters in name after the last slash. + If name contains no slashes then return name. +
+
+file tempfile ?template? +: +
+ Creates and returns the name of a unique temporary file. If template is 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 of file, directory, characterSpecial, + blockSpecial, fifo, link, or socket. +
+
+file writable name +: +
+ Return 1 if file name is 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]} then {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, REFERENCES, LAMBDA for more detail.

flush

flush fileId

fileId flush

Flushes any output that has been buffered for fileId. fileId must +have been the return value from a previous call to open, or it may be +stdout or stderr to access one of the standard I/O streams; it must +refer to a file that was opened for writing. This command returns an +empty string.

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.

If a break command is invoked within body or next, then the for +command will return immediately.

The operation of break and continue are similar to the corresponding +statements in C.

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 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 character value.

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, REFERENCES, LAMBDA for more detail.

gets

gets fileId ?varName?

fileId gets ?varName?

Reads the next line from the file given by fileId and discards +the terminating newline character.

If varName is 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 and varName is set to an +empty string.

If varName is 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, so eof may have to be used to determine +what really happened.

If the last character in the file is not a newline character, then +gets behaves as if there were an additional newline character +at the end of the file.

fileId must be stdin or the return value from a previous +call to open; it must refer to a file that was opened +for reading.

glob

glob ?-nocomplain? 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.

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) 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 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. Procname must be the name of a + Tcl command procedure. +
+
+info body procname +: +
+ Returns the body of procedure procname. Procname must be + the name of a Tcl command procedure. +
+
+info commands ?pattern? +: +
+ If pattern isn’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 the proc command. + If pattern is specified, only those names matching pattern + are returned. Matching is determined using the same rules as for + string match. +
+
+info complete command +: +
+ Returns 1 if command is 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. +
+
+info exists varName +: +
+ Returns 1 if the variable named varName exists in the + current context (either as a global or local variable), returns 0 + otherwise. +
+
+info frame ?number? +: +
+ If number is not specified, this command returns a number + which is the same result as info level - the current stack frame level. + If number is specified, then the result is a list consisting of the procedure, + filename and line number for the procedure call at level number on the stack. + If number is 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). + The level has an identical meaning to info level. +
+
+info globals ?pattern? +: +
+ If pattern isn’t specified, returns a list of all the names + of currently-defined global variables. + If pattern is specified, only those names matching pattern + are returned. Matching is determined using the same rules as for + string match. +
+
+info hostname +: +
+ An alias for os.gethostname for compatibility with Tcl 6.x +
+
+info level ?number? +: +
+ If number is 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. If number is specified, + then the result is a list consisting of the name and arguments for the + procedure call at level number on the stack. If number + is 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 the uplevel command for more information on what stack + levels mean. +
+
+info locals ?pattern? +: +
+ If pattern isn’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 the global + and upvar commands will not be returned. If pattern is + specified, only those names matching pattern are returned. + Matching is determined using the same rules as for string match. +
+
+info nameofexecutable +: +
+ Returns the name of the binary file from which the application + was invoked, either + as a path relative to the current directory or as a full + path. If the path can’t be determined, returns the empty + string. +
+
+info procs ?pattern? +: +
+ If pattern isn’t specified, returns a list of all the + names of Tcl command procedures. + If pattern is specified, only those names matching pattern + are returned. Matching is determined using the same rules as for + string match. +
+
+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 source command), then this command returns the name + of the innermost file being processed. Otherwise the command returns an + empty string. +
+
+info source script +: +
+ 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. +
+
+info stacktrace +: +
+ After an error is caught with catch, returns the stack trace as a list + of {procedure filename line …}. +
+
+info version +: +
+ Returns the version number for this version of Jim in the form x.yy. +
+
+info vars ?pattern? +: +
+ If pattern isn’t specified, + returns a list of all the names of currently-visible variables, including + both locals and currently-visible globals. + If pattern is specified, only those names matching pattern + are returned. Matching is determined using the same rules as for + string match. +
+

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, REFERENCES, LAMBDA 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 $b is 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 ele- +ments than variables, a list of unassigned elements is returned.

jim> lassign {1 2 3} a b; puts a=$a,b=$b
+3
+a=1,b=2

local

local args

Executes it’s arguments as a command (per eval) and considers the return +value to be a procedure name, which is marked as having local scope. +This means that when the current procedure exits, the specified +procedure is deleted. This can be useful with lambda or simply +local procedures.

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.

proc outer {} {
+  set x [lambda inner {args} {
+    # will be deleted when 'outer' exits
+  }]
+  # Use 'function' here which simply returns $x
+  local function $x

  $x ...
+  ...
+}

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 index is negative or greater than or equal to the number of elements +in value, then an empty string is returned.

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 index 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 a decimal string giving +the number of elements in it.

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 newValue

In 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 newValue

replaces 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

lmap is a "collecting foreach" which returns a list of its results.

For example:

jim> lmap i {1 2 3 4 5} {expr $i*$i}
+1 4 9 16 25
+jim> lmap a {1 2 3} b {A B C} {list $a $b}
+{1 A} {2 B} {3 C}

If the body invokes continue, no value is added for this iteration. +If the body invokes break, the loop ends and no more values are added.

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.

Note: lrange list first first does not always produce the +same result as lindex list first (although it often does +for simple fields that aren’t enclosed in braces); it does, however, +produce exactly the same results as list [lindex list first]

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).

jim> lrepeat 3 a b
+a b a b a b

lreverse

lreverse list

Returns the list in reverse order.

jim> lreverse {1 2 3}
+3 2 1

lsearch

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 +: +
+ pattern is a literal string that is compared for exact equality against each list element. + This is the default. +
+
+-glob +: +
+ pattern is a glob-style pattern which is matched against each list element using the same + rules as the string match command. +
+
+-regexp +: +
+ pattern is treated as a regular expression and matched against each list element using + the rules described by regexp. +
+
+-all +: +
+ Changes the result to be the list of all matching indices (or all matching values if + -inline is 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 -all is also specified, then the result of the command is the list of all + values that matched. The -inline and -bool options are mutually exclusive. +
+
+-bool +: +
+ Changes the result to 1 if a match was found, or 0 otherwise. If -all is 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 -inline and -bool options are mutually exclusive. +
+
+-not +: +
+ This negates the sense of the match, returning the index (or value + if -inline is specified) of the first non-matching value in the + list. If -bool is also specified, the 0 will be returned if a + match is found, or 1 otherwise. If -all is also specified, + non-matches will be returned rather than matches. +
+
+-nocase +: +
+ Causes comparisons to be handled in a case-insensitive manner. +
+

lsort

lsort ?-integer|-command cmdname? ?-decreasing|-increasing? list

Sort the elements of list, returning a new list in sorted order. +By default, ASCII sorting is used, with the result in increasing order.

If -integer is specified, numeric sorting is used.

If -command cmdname is specified, cmdname is treated as a +command name. For each comparison, cmdname $value1 $value2 is called +which should return -1 if $value1 is less than $value2, 0 if +they are equal, or 1 otherwise.

If -decreasing is specified, the resulting list is in the opposite +order to what it would be otherwise. -increasing is the default.

open

open fileName ?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.

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.

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.

The pid command may be used to return the process ids of the commands +forming the command pipeline.

package

package provide name ?version?

Indicates that the current script provides the package named name. +If no version is specified, 1.0 is used.

Any script which 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 name by examining each path +in $::auto_path and trying to load $path/$name.tcl.

If either file exists, it is loaded with source.

Typically $::auto_path contains the paths . and /lib/jim.

pid

pid

pid fileId

The first form returns the process identifier of the current process.

The second form accepts a handle returned by open and returns a list +of the process ids forming the pipeline in the same form as exec … &. +If fileId represents a regular file handle rather than a command pipeline, +the empty string is returned instead.

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, static, declares static variables which are bound to the +procedure.

See PROCEDURES for detailed information about Tcl procedures.

The proc command returns name (which is useful with local).

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

fileId puts ?-nonewline? string

Writes the characters given by string to the file given +by fileId. fileId must have been the return +value from a previous call to open, or it may be +stdout or stderr to refer to one of the standard I/O +channels; it must refer to a file that was opened for +writing.

In the first form, if no fileId is specified then it defaults to stdout. +puts normally outputs a newline character after string, +but this feature may be suppressed by specifying the -nonewline +switch.

Output to files is buffered internally by Tcl; the flush +command may be used to force buffered characters to be output.

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).

jim> range 5
+0 1 2 3 4
+jim> range 2 5
+2 3 4
+jim> range 2 10 4
+2 6
+jim> range 7 4 -2
+7 5

read

read ?-nonewline? fileId

fileId read ?-nonewline?

read fileId numBytes

fileId read numBytes

In the first form, all of the remaining bytes are read from the file +given by fileId; they are returned as the result of the command. +If the -nonewline switch is specified then the last +character of the file is discarded if it is a newline.

In the second form, the extra argument specifies how many bytes to read; +exactly this many bytes will be read and returned, unless there are fewer than +numBytes bytes left in the file; in this case, all the remaining +bytes are returned.

fileId must be stdin or the return value from a previous call +to open; it must refer to a file that was opened for reading.

regexp

regexp ?-nocase? ?-line? ?-indices? ?-start offset? ?-all? ?-inline? ?--? 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, a anchor matches the null + string after any newline in the string in addition to its normal + function, and the $ anchor matches the null 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 -indices is + specified, the indices will be indexed starting from the + absolute beginning of the input string. offset will 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. +
+
+-- +: +
+ Marks the end of switches. The argument following this one will be + treated as exp even if it starts with a -. +
+

regsub

regsub ?-nocase? ?-all? ?-line? ?-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 susbstitutions 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 string are converted to lower-case + before matching against exp; however, substitutions + specified by subSpec use the original unconverted form + of string. +
+
+-all +: +
+ All ranges in string that match exp are found and substitution + is performed for each of these ranges, rather than only the + first. The & and \n sequences 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, a anchor matches the null + string after any newline in the string in addition to its normal + function, and the $ anchor matches the null string before any + newline in the string in addition to its normal function. +
+
+-start offset +: +
+ Specifies a character index offset into the string at which to + start matching the regular expression. offset will be + constrained to the bounds of the input string. +
+
+-- +: +
+ Marks the end of switches. The argument following this one will be + treated as exp even 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 string'+

See GARBAGE COLLECTION, REFERENCES, LAMBDA 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.

seek

seek fileId offset ?origin?

fileId seek offset ?origin?

Change the current access position for fileId. +The offset and origin arguments specify the position at +which the next read or write will occur for fileId. +offset must be a number (which may be negative) and origin +must be one of the following:

+start +: +
+ The new access position will be offset bytes from the start + of the file. +
+
+current +: +
+ The new access position will be offset bytes from the current + access position; a negative offset moves the access position + backwards in the file. +
+
+end +: +
+ The new access position will be offset bytes from the end of + the file. A negative offset places the access position before + the end-of-file, and a positive offset places the access position + after the end-of-file. +
+

The origin argument defaults to start.

fileId must have been the return value from a previous call to +open, or it may be stdin, stdout, or stderr to refer to one +of the standard I/O channels.

This command returns an empty string.

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, REFERENCES, LAMBDA 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 -signal or try -signal. Use + signal check to determine which signals have occurred but + been ignored. +

+signal default ?signals …? +

+ If no signals are given, returns a lists all signals which are 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 -clear is specified, any signals returned are removed and will not be + returned by subsequent calls to signal check unless delivered again. +

+signal throw ?signal? +

+ Raises the given signal, which defaults to SIGINT if 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
+}

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.

If a return command is invoked from within the file, the remainder of +the file will be skipped and the source command will return +normally with the result from the return command.

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 proc file line …. +Iteratively uses info frame to create the stack trace. This stack trace is in the +same form as produced by catch and info stacktrace

string

string option arg ?arg …?

Perform one of several string operations, depending on option. +The legal options (which may be abbreviated) are:

+string compare ?-nocase? string1 string2 +

+ Perform a character-by-character comparison of strings string1 and + string2 in the same way as the C strcmp procedure. Return + -1, 0, or 1, depending on whether string1 is lexicographically + less than, equal to, or greater than string2. + Performs a case-insensitive comparison if -nocase is specified. +

+string equal ?-nocase? string1 string2 +

+ Returns 1 if the strings are equal, or 0 otherwise. + Performs a case-insensitive comparison if -nocase is specified. +

+string first string1 string2 ?firstIndex? +

+ Search string2 for a sequence of characters that exactly match + the characters in string1. If found, return the index of the + first character in the first such match within string2. If not + found, return -1. If firstIndex is specified, matching will start + from firstIndex of string1. +

+ +

+ See STRING AND LIST INDEX SPECIFICATIONS for all allowed forms for firstIndex. +

+string index string charIndex +

+ Returns the charIndex'th character of the string + argument. A charIndex of 0 corresponds to the first + character of the string. + If charIndex is 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 string is a valid member of the specified character + class, otherwise returns 0. If -strict is 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). +
+
+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]). +
+

+string last string1 string2 ?lastIndex? +

+ Search string2 for a sequence of characters that exactly match + the characters in string1. If found, return the index of the + first character in the last such match within string2. If there + is no match, then return -1. If lastIndex is specified, only characters + up to lastIndex of string2 will 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. +

+string match ?-nocase? pattern string +

+ See if pattern matches string; return 1 if it does, 0 + if it doesn’t. Matching is done in a fashion similar to that + used by the C-shell. For the two strings to match, their contents + must be identical except that the following special sequences + may appear in pattern: +

+* +: +
+ Matches any sequence of characters in string, + including a null string. +
+
+? +: +
+ Matches any single character in string. +
+
+[chars] +: +
+ Matches any character in the set given by chars. + If a sequence of the form x-y appears in chars, + then any character between x and y, inclusive, + will match. +
+
+\x +: +
+ Matches the single character x. This provides a way of + avoiding the special interpretation of the characters `\*?[]\` + in pattern. +
+

+ +

+ Performs a case-insensitive comparison if -nocase is specified. +

+string range string first last +

+ Returns a range of consecutive characters from string, starting + with the character whose index is first and ending with the + character whose index is last. An index of 0 refers to the + first character of the string. +

+ +

+ See STRING AND LIST INDEX SPECIFICATIONS for all allowed forms for first and last. +

+ +

+ If first is less than zero then it is treated as if it were zero, and + if last is greater than or equal to the length of the string then + it is treated as if it were end. If first is greater than + last then an empty string is returned. +

+string repeat string count +

+ Returns a new string consisting of string repeated count times. +

+string reverse string +

+ Returns a string that is the same length as string but + with its characters in the reverse order. +

+string tolower string +

+ Returns a value equal to string except that all upper case + letters have been converted to lower case. +

+string toupper string +

+ Returns a value equal to string except that all lower case + letters have been converted to upper case. +

+string trim string ?chars? +

+ Returns a value equal to string except that any leading + or trailing characters from the set given by chars are + removed. + If chars is not specified then white space is removed + (spaces, tabs, newlines, and carriage returns). +

+string trimleft string ?chars? +

+ Returns a value equal to string except that any + leading characters from the set given by chars are + removed. + If chars is not specified then white space is removed + (spaces, tabs, newlines, and carriage returns). +

+string trimright string ?chars? +

+ Returns a value equal to string except that any + trailing characters from the set given by chars are + removed. + If chars is 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: 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 + matching (i.e. the same as implemented by the string + match command). +
+
+-regexp +: +
+ When matching string to the patterns, use regular + expression matching (i.e. the same as implemented + by the regexp command). +
+
+-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 behavior 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 a b c]

tailcall is useful for a dispatch mechanism:

proc a {cmd args} {
+  tailcall sub_$cmd {*}$args
+}
+proc sub_cmd1 ...
+proc sub_cmd2 ...

tell

tell fileId

fileId tell

Returns a decimal string giving the current access position in +fileId.

fileId must have been the return value from a previous call to +open, or it may be stdin, stdout, or stderr to refer to one +of the standard I/O channels.

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 iteration

which indicates the average amount of time required per iteration, +in microseconds.

Time is measured in elapsed time, not CPU time.

try

try ?catchopts? tryscript ?on returncodes {?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 handler +(there many be zero or more) based on the return code 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.

The specified returncodes is a list of return codes either as names (ok, error, break, etc.) +or as integers.

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 $f
+} on {continue break} {} {
+    error "Unexpected break/continue"
+} on error {msg opts} {
+    puts "Dealing with error"
+    return {*}$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.

In any case, the file will be closed via the finally clause.

See also throw, catch, return, error.

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 interpeter 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.

In some cases (such as expanding abbreviations) unknown will +change the original command slightly and then (re-)execute it. +The result of the unknown command is used as the result for +the original non-existent command.

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.

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}

then the set command will modify the same variable x in b’s +context: the procedure 'c does not appear to be on the call stack +when d is executing. The command info level may +be used to obtain the level of the current procedure.

Uplevel makes it possible to implement new control +constructs as Tcl procedures (for example, uplevel could +be used to implement the while construct as a Tcl procedure).

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]
+}

Add2 is invoked with an argument giving the name of a variable, +and it adds two to the value of that variable. +Although add2 could have been implemented using uplevel +instead of upvar, upvar makes it simpler for add2 +to access the variable in the caller’s procedure frame.

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.

OPTIONAL-EXTENSIONS

The following extensions may or may not be available depending upon +what options were selected when Jim Tcl was built.

bio

The bio command provides a way to read and write binary files +from within Tcl. Note that since Jim supports binary strings, the +main use of this command is bio copy to easily copy between file +descriptors.

+bio read ?-hex? fd var numbytes +: +
+ Read bytes from a file descriptor. By default the data is not encoded. + Using -hex encodes the data as ascii hex instead. Returns + the number of bytes actually read. +
+
+bio write ?-hex? fd buf +: +
+ Write a string to a file descriptor. If -hex is specified, the + string is expected to be in ascii hexx format. Returns the number + of bytes actually written. +
+
+bio copy fromfd tofd ?numbytes? +: +
+ Copy binary data from the file descriptor fromfd to the + file descriptor tofd. If numbytes is specified, at most that many + bytes will be copied. Otherwise copying continues until the end + of the input file. Returns the number of bytes actually copied. +
+

posix: os.fork, os.wait, os.gethostname, os.getids, os.uptime

+os.fork +

+ Invokes fork(2) and returns the result. +

+os.wait -nohang pid +

+ Invokes waitpid(2), with WNOHANG if -nohang is specified. + Returns a list of 3 elements. +

{0 none 0} if -nohang is specified, and the process is still alive.

{-1 error <error-description>} if the process does not exist or has already been waited for.

{<pid> exit <exit-status>} if the process exited normally.

{<pid> signal <signal-number>} if the process terminated on a signal.

{<pid> other 0} otherwise (core dump, stopped, continued, etc.)

+os.gethostname +

+ Invokes gethostname(3) and returns the result. +

+os.getids +

+ Returns the various user/group ids for the current process. +

jim> os.getids
+uid 1000 euid 1000 gid 100 egid 100

+os.uptime +

+ Returns the number of seconds since system boot. See description of uptime in sysinfo(2). +

ANSI I/O (aio) and EVENTLOOP API

Jim provides an alternative object-based API for I/O.

See open and socket for commands which return an I/O handle.

aio

+$handle read ?-nonewline? ?len? +: +
+ Read and return bytes from the stream. To eof if no len. +
+
+$handle gets ?var? +: +
+ Read one line and return it or store it in the var +
+
+$handle puts ?-nonewline? str +: +
+ Write the string, with newline unless -nonewline +
+
+$handle flush +: +
+ Flush the stream +
+
+$handle eof +: +
+ Returns 1 if stream is at eof +
+
+$handle close +: +
+ Closes the stream +
+
+$handle seek offset ?start|current|end? +: +
+ Seeks in the stream (default current) +
+
+$handle tell +: +
+ Returns the current seek position +
+
+$handle ndelay ?0|1? +: +
+ Set O_NDELAY (if arg). Returns current/new setting. + Note that in general ANSI I/O interacts badly with non-blocking I/O. + Use with care. +
+
+$handle accept +: +
+ Server socket only: Accept a connection and return stream +
+
+$handle sendto str ?hostname:?port +: +
+ Sends the string, str, to the given address via the socket using sendto(2). + This is intended for udp sockets and may give an error or behave in unintended + ways for other handle types. + Returns the number of bytes written. +
+
+$handle recvfrom maxlen ?addrvar? +: +
+ Receives a message from the handle via recvfrom(2) and returns it. + At most maxlen bytes are read. + If addrvar is specified, the sending address of the message is stored in + the named variable in the form addr:port. See socket for details. +
+

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 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 vwait or update. The script is only run once and + then removed. Returns an event id. +
+
+after cancel id|command +: +
+ Cancels an after event 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 id is not given, returns a list of current after + events. If id is given, returns a list containing the + associated script and either timer or idle to indicated + the type of the event. An error occurs if id does not + match an event. +
+
+vwait variable +: +
+ A call to vwait is enters the eventloop. vwait processes + 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, vwait + returns immediately. +
+
+update ?idletasks? +: +
+ A call to update enters 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 commands does not exist, it is 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 error +: +
+ Called when an event handler script generates an error. +
+

socket

Various socket types may be created.

+socket unix path +: +
+ A unix domain socket client. +
+
+socket unix.server path +: +
+ A unix domain socket server. +
+
+socket ?-ipv6? stream addr:port +: +
+ A TCP socket client. +
+
+*socket ?-ipv6? stream.server ?addr:?port +: +
+ A TCP socket server (addr defaults to 0.0.0.0 for IPv4 or [::] for IPv6). +
+
+socket ?-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. +
+
+socket ?-ipv6? dgram.server addr:port +: +
+ A UDP socket server. +
+
+socket pipe +: +
+ A pipe. Note that unlike all other socket types, this command returns + a list of two channels: {read write} +
+

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 close

Server 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 done

The 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.

The special type pipe isn’t really a socket.

lassign [socket pipe] r w

# Must close $w after exec
+exec ps >@$w &
+$w close

$r readable ...

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, debug

If 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. +

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 env command. + It may be modified and will affect the environment passed to + commands invoked with exec. +
+
+auto_path +: +
+ This variable contains a list of paths to search for packages. + It contains {. /lib/jim} by default. +
+
+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 exec sets this variable. + Otherwise it will be NONE. +
+

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. +
+
+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. +
+
+jim_argv0 +: +
+ The value of argv[0] when jimsh was invoked. +
+

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>

The FreeBSD license

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.

+Jim Tcl(n) Manual Page +

NAME

SYNOPSIS

INTRODUCTION

CHANGES

TCL INTRODUCTION

INTERPRETERS

DATA TYPES

BASIC COMMAND SYNTAX

COMMENTS

GROUPING ARGUMENTS WITH DOUBLE-QUOTES

GROUPING ARGUMENTS WITH BRACES

COMMAND SUBSTITUTION WITH BRACKETS

VARIABLE SUBSTITUTION WITH $

SEPARATING COMMANDS WITH SEMI-COLONS

BACKSLASH SUBSTITUTION

STRING AND LIST INDEX SPECIFICATIONS

COMMAND SUMMARY

EXPRESSIONS

LISTS

LIST EXPANSION

REGULAR EXPRESSIONS

COMMAND RESULTS

PROCEDURES

VARIABLES - SCALARS AND ARRAYS

ARRAYS AS LISTS IN JIM

DICTIONARY VALUES

GARBAGE COLLECTION, REFERENCES, LAMBDA

References

Garbage Collection

Lambda

BUILT-IN COMMANDS

Command Index

alarm

alias

append

array

break

case

catch

cd

clock

close

collect

concat

continue

curry

dict

env

eof

error

errorInfo

eval

exec

exit

expr

file

finalize

flush

for

foreach

format

getref

gets

glob

global

if

incr

info

join

kill

lambda

lappend

lassign

local

lindex

linsert

list

llength

lset