Re: Suggested Technique

Hi Martin,
 
<snip>
While I understand the idea of DO *hival coupled with a leave, why not just
say it in the first place, and have a DOU F3 and avoid the extra lines of
coding? DOU F3 is pretty clear, too, isn't it?
</snip>
 
I agree. But in the scenario where there are three different reasons why I
would leave the screen loop, each also requiring a separate and distinct
action, then I would rather couple the "action" and the "leave" to make it
obvious to me.
 
Examples: 
 
1)
 
DOU F3
        or someFlag
        or someOtherFlag
        or yetAnotherFlag
 
exfmt screen
 
select
 
when F3
// do nothing, just waiting to hit the bottom...
 
when someCondition
doSomethingClever()
someFlag = *on
 
when someOtherCondition
doSomethingEvenMoreClever()
someOtherFlag = *on
 
when yetAnotherCondition
doSomethingBoring()
yetAnotherFlag = *on
endsl
 
.some other code...
 
ENDDO
 
 
2)
 
DO *hival
 
exfmt screen
 
if F3
leave
endif
 
if someCondition
doSomethingClever()
someFlag = *on
leave
endif
 
if someOtherCondition
doSomethingEvenMoreClever()
someOtherFlag = *on
leave
endif
 
if yetAnotherCondition
doSomethingBoring()
yetAnotherFlag = *on
leave
endif
 
.some other code...
 
ENDDO
 
Personally, I prefer the fact that my action and my explicit leave are
"coupled". I don't have to look in two places to see why I find myself
outside the loop. If I'm having to code for the actions anyway then it's
easier (for me) to complete the code with the leave, rather than add another
condition on an already overloaded DO. It can't get more obvious to another
programmer than code stating "do something then leave". Also, I don't like
the fact that I would need a redundant "when" clause for F3.
 
I suppose it boils down to the fact that I consider a screen DO loop as
nothing more than a "code container" that has no implicit logic - it's just
a construct. I code my exit strategy within this construct. This, of course,
does not mean that I code all DO or FOR loops this way.
 
Again, just a preference.
 
Cheers
 
Larry Ducie