Nested Gosubs

[Nancy Palmquist]

I have enjoyed this thread and all the references to me.  I guess I 
should have hung around yesterday (SUNDAY) instead of wasting my time 
watching the Steelers tromp on New England Or go trick or treating.

But it looks like Mark understands the posting I did early in the day.

I would like to clarify some processing logic.

You have to look at the input processing as containing different tables 
entirely.

TYPES OF PROCESSING
1) INPUT FLOW PROCESSING.
You have the normal input processing or any @key processing logic -
This logic starts at line 1 or the @key label depending on what is 
appropriate.  The logic continues forward until an END or EXIT.  During 
the flow, the processing goes back and forth between the User having 
control with a data entry opportunity or the processing having control.

2) WHEN PROCESSING
These are little baby programs that are TRIGGERED by an event such as 
When Entering or leaving a field.  When a key is hit in a data field, 
and other field related events.  These processes are in the same table 
as type 1 but they function independently and may or may not happen 
depending on the triggering event.  These are closed with END, SCREEN, 
RESTART, SKIP

3) @once, @done, @menu  - these offer processing that is not record 
related but happen as a prefix or post script to the session.  They are 
processed until an END or EXIT statement.

4) @entsel - processing that occurs before a record is displayed and is 
usually used to display browses, lookup data, or change the user prompts.

Now only in TYPE 1 does the END command really signal the end to a 
records processing.

EXIT used anywhere always means EXIT so that would throw your butt out 
in any context.

Now since the WHEN processing and the INPUT processing share the same 
table, it sometimes happens that you try to share a subroutine.  Well 
and good, but that is where you must be careful that the subroutine does 
not contain any condition where it issues a command that the WHEN would 
react to as a end command but was really intended to be treated differently.

@wlf1
	then: gosub calc
	if: 12 gt "1"
	then: msgbox "HERE I AM";end

calc	
	then: 12=1+2
	if:	12 gt "1"
	then: errorbox "YOU MADE A BOO BOO";screen,2;goto calc
	then:return
Now in this little sample.  WLF1 it will run the calc routine.  If 12 gt 
"1", it will put the user in field 2.  The RETURN was not run.  So one 
RETURN is now hanging.

It will also never display the msgbox "HERE I AM" because it will never 
return from the gosub.

That is what you have to control.  You have to keep two streams of logic 
seperate and know if you are running a routine from input, WHEN's or 
both and structure it correctly.

Nancy




-- 
Nancy Palmquist
Virtual Software Systems
PHONE: (412) 835-9417			Web site:  http://www.vss3.com