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authorrjohnson <rjohnson>1998-03-26 14:45:59 (GMT)
committerrjohnson <rjohnson>1998-03-26 14:45:59 (GMT)
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+'\"
+'\" Copyright (c) 1993 The Regents of the University of California.
+'\" Copyright (c) 1994-1997 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: @(#) for.n 1.6 97/04/08 17:13:49
+'\"
+.so man.macros
+.TH for n "" Tcl "Tcl Built-In Commands"
+.BS
+'\" Note: do not modify the .SH NAME line immediately below!
+.SH NAME
+for \- ``For'' loop
+.SH SYNOPSIS
+\fBfor \fIstart test next body\fR
+.BE
+
+.SH DESCRIPTION
+.PP
+\fBFor\fR is a looping command, similar in structure to the C
+\fBfor\fR statement. The \fIstart\fR, \fInext\fR, and
+\fIbody\fR arguments must be Tcl command strings, and \fItest\fR
+is an expression string.
+The \fBfor\fR command first invokes the Tcl interpreter to
+execute \fIstart\fR. Then it repeatedly evaluates \fItest\fR as
+an expression; if the result is non-zero it invokes the Tcl
+interpreter on \fIbody\fR, then invokes the Tcl interpreter on \fInext\fR,
+then repeats the loop. The command terminates when \fItest\fR evaluates
+to 0. If a \fBcontinue\fR command is invoked within \fIbody\fR then
+any remaining commands in the current execution of \fIbody\fR are skipped;
+processing continues by invoking the Tcl interpreter on \fInext\fR, then
+evaluating \fItest\fR, and so on. If a \fBbreak\fR command is invoked
+within \fIbody\fR
+or \fInext\fR,
+then the \fBfor\fR command will
+return immediately.
+The operation of \fBbreak\fR and \fBcontinue\fR are similar to the
+corresponding statements in C.
+\fBFor\fR returns an empty string.
+.PP
+Note: \fItest\fR should almost always be enclosed in braces. If not,
+variable substitutions will be made before the \fBfor\fR
+command starts executing, which means that variable changes
+made by the loop body will not be considered in the expression.
+This is likely to result in an infinite loop. If \fItest\fR is
+enclosed in braces, variable substitutions are delayed until the
+expression is evaluated (before
+each loop iteration), so changes in the variables will be visible.
+For an example, try the following script with and without the braces
+around \fB$x<10\fR:
+.CS
+for {set x 0} {$x<10} {incr x} {
+ puts "x is $x"
+}
+.CE
+
+.SH KEYWORDS
+for, iteration, looping