Version 0 of loop

Updated 2002-06-11 12:47:52

Tclx documents the loop command as:

     loop var first limit ?increment? body

          Loop is a looping command, similar in behavior to the Tcl
          for statement, except that the loop statement achieves
          substantially higher performance and is easier to code when
          the beginning and ending values of a loop are known, and the
          loop variable is to be incremented by a known, fixed amount
          every time through the loop.

          The var argument is the name of a Tcl variable that will
          contain the loop index. The loop index is set to the value
          specified by first. The Tcl interpreter is invoked upon body
          zero or more times, where var is incremented by increment
          every time through the loop, or by one if increment is not
          specified. Increment can be negative in which case the loop
          will count down- wards.

          When var reaches limit, the loop terminates without a
          subsequent execution of body. For instance, if the original
          loop parameters would cause loop to terminate, say first was
          one, limit was zero and increment was not specified or was
          non-negative, body is not executed at all and loop returns.

          The first, limit and increment are integer expressions. They
          are only evaluated once at the beginning of the loop.

          If a continue command is invoked within body then any
          remaining commands in the current execution of body are
          skipped, as in the for command. If a break command is invoked
          within body then the loop command will return immediately.
          Loop returns an empty string.


Category Command, a part of Tclx