HP 3000 Manuals

HP ALLBASE/4GL Developer Self-Paced Training Guide

Full Data Screen Processing 

This order of processing controls the way the cursor moves from field to
field, and how the screen is completed.

The numbers in the following description refer to the step numbers in the
diagrams.


            

   1.  When HP ALLBASE/4GL displays a data screen, the display field
       processing is invoked for the first screen field.  (This
       processing is described later.)

   2.  HP ALLBASE/4GL tests the value in the *FIELDNO communication area
       field.  *FIELDNO is a communication area field containing the
       number of the current screen field.  This value can be set with
       the MOVE command to explicitly move a screen field number to
       *FIELDNO. If *FIELDNO has been set, control passes immediately to
       the field specified in *FIELDNO. Otherwise processing continues
       normally.

   3.  The current field is tested to check if it allows data input.  If
       it does, processing continues; otherwise it branches to step 5.

   4.  Input field processing is performed.  (This is described later.)

   5.  At the end of the input field processing, HP ALLBASE/4GL tests the
       contents of *FIELDNO again.  If the *FIELDNO value has been
       changed during input field processing, control passes to the field
       indicated by the new value in *FIELDNO. Otherwise processing
       continues normally.

   6.  This step tests the communication area field *NEWTIE to determine
       if it has been altered during input field processing.  *NEWTIE is
       a communication area field that contains the number of the next
       field to be processed.  If

   7.  NEWTIE has been altered, control passes to the screen field
       indicated by the value in *NEWTIE. Otherwise processing continues
       normally.

       The value in *NEWTIE can be set by moving a new value to it, or by
       the TIE logic command.  The TIE command takes a screen field name
       as its argument and moves its number to

   8.  NEWTIE.

   9.  Next HP ALLBASE/4GL determines if there are any more fields on the
       screen.  If so, control passes to the next screen field.

  10.  At the end of the screen, one of two things can occur.  If the
       screen has input fields, the cursor remains on the last input
       field.  If the screen doesn't have any input fields, the cursor is
       positioned at the base of the screen.  In both cases, the system
       waits for the user to press a valid function key.

  11.  This step resets system values such as *FIELDNO and *NEWTIE and
       passes control to the next field.

MPE/iX 5.0 Documentation