68 lines
2.5 KiB
Plaintext
68 lines
2.5 KiB
Plaintext
'\"
|
|
'\" Copyright (c) 1993-1997 Bell Labs Innovations for Lucent Technologies
|
|
'\" Copyright (c) 1997 Sun Microsystems, Inc.
|
|
'\"
|
|
'\" See the file "license.terms" for information on usage and redistribution
|
|
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
|
|
'\"
|
|
'\" SCCS: @(#) variable.n 1.2 97/05/18 15:20:28
|
|
'\"
|
|
.so man.macros
|
|
.TH variable n 8.0 Tcl "Tcl Built-In Commands"
|
|
.BS
|
|
'\" Note: do not modify the .SH NAME line immediately below!
|
|
.SH NAME
|
|
variable \- create and initialize a namespace variable
|
|
.SH SYNOPSIS
|
|
\fBvariable \fR?\fIname value...\fR? \fIname \fR?\fIvalue\fR?
|
|
.BE
|
|
|
|
.SH DESCRIPTION
|
|
.PP
|
|
This command is normally used within a
|
|
\fBnamespace eval\fR command to create one or more variables
|
|
within a namespace.
|
|
Each variable \fIname\fR is initialized with \fIvalue\fR.
|
|
The \fIvalue\fR for the last variable is optional.
|
|
.PP
|
|
If a variable \fIname\fR does not exist,
|
|
it is created and given the optional \fIvalue\fR.
|
|
If it already exists, it is simply set to the optional \fIvalue\fR.
|
|
Normally, \fIname\fR is unqualified
|
|
(does not include the names of any containing namespaces),
|
|
and the variable is created in the current namespace.
|
|
If \fIname\fR includes any namespace qualifiers,
|
|
the variable is created in the specified namespace.
|
|
.PP
|
|
If the \fBvariable\fR command is executed inside a Tcl procedure,
|
|
it creates local variables
|
|
linked to the corresponding namespace variables.
|
|
In this way the \fBvariable\fR command resembles the \fBglobal\fR command,
|
|
although the \fBglobal\fR command
|
|
only links to variables in the global namespace.
|
|
If any \fIvalue\fRs are given,
|
|
they are used to modify the values of the associated namespace variables.
|
|
If a namespace variable does not exist,
|
|
it is created and optionally initialized.
|
|
.PP
|
|
A \fIname\fR argument cannot reference an element within an array.
|
|
Instead, \fIname\fR should reference the entire array,
|
|
and the initialization \fIvalue\fR should be left off.
|
|
After the variable has been declared,
|
|
elements within the array can be set using ordinary
|
|
\fBset\fR or \fBarray\fR commands.
|
|
.PP
|
|
It is generally best to provide a \fIvalue\fR to initialize each variable,
|
|
or to initialize it immediately after the \fBvariable\fR command.
|
|
This is because a namespace variable declared by a \fBvariable\fR command
|
|
is not actually created until it is given a value.
|
|
A declared but not yet initialized namespace variable
|
|
will not appear in the output of an \fBinfo vars\fR command,
|
|
for example.
|
|
|
|
.SH "SEE ALSO"
|
|
global(n), namespace(n)
|
|
|
|
.SH KEYWORDS
|
|
global, namespace, procedure, variable
|