
Cantata(Control)             Khoros              Cantata(Control)

     CONTROL STRUCTURES

     Control structures are used to create more complex visual
     programs by providing looping and decision constructs.

     OVERVIEW

     A specific programming control structure is selected by
     clicking on the appropriate button from the "guide pane" on
     the left of the subform.  Once the desired structure has
     been selected, a pane will appear on the right of the sub-
     form with parameter values which may then be modified.
     Additional documentation for each control structure is
     available under `Help' on the pane for that structure.

     All control glyphs have an extra button at the top of the
     glyph.  This `RESET' button is used to set the glyph so that
     when next run, the initial input to the glyph will be
     accepted and the initialization steps re-executed.

     Glyph connection names for control glyphs represent "flow of
     control" as well as "flow of data".   The flow of data is
     explicitly determined by the connections made, but the flow
     of control is implied by your program structure.  As an
     example, the Count-Loop discussed later can accept a feed-
     back path from anywhere in the sequence of glyphs that are
     connected to its output, but the entire sequence is assumed
     to be part of the loop.  (See examples of no feedback vs.
     with feedback).

     SHORT DESCRIPTIONS

     Count-Loop     Used to create a counting loop similar to a
                    for or DO loop..

     While-Loop     Used to create a conditional loop.

     If-Then-Else   Used to create a decision structure or pro-
                    gram branching.

     Merge          Used to merge two data paths together (as at
                    the end of an If-Then-Else).

                    Copyright 1991, University of New Mexico. All
                    rights reserved.

Version: 0                 Release: 1                           1

