archie/tcl7.6/doc/for.n

'\"
'\" Copyright (c) 1993 The Regents of the University of California.
'\" Copyright (c) 1994-1996 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 1.5 96/03/25 20:15:01
'\" 
.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.

.SH KEYWORDS
for, iteration, looping