NAME
       for - ``For'' loop

SYNOPSIS
       for start test next body


DESCRIPTION
       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  exe-
       cute  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  immedi-
       ately.  The operation of break and continue are similar to
       the corresponding statements in C.  For returns  an  empty
       string.

       Note: test should almost always be enclosed in braces.  If
       not, variable substitutions will be made  before  the  for
       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 test is enclosed in braces,  variable  substitu-
       tions  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 $x<10:
              for {set x 0} {$x<10} {incr x} {
                puts "x is $x"
              }


SEE ALSO
       break, continue, foreach, while


KEYWORDS
       for, iteration, looping
