AW: AW: No Subroutines (was Re: Debugging many subprocedures)

Rob,

We added these return subroutines to avoid duplicate code
and to not forget some essential details, like COMMIT
or repassing optional parameters or storing static variables.

Today it's quite neccessary because we have not yet procedures/functions for
all and everything.
If we'll have finished our redesign, we'll only have procedures containing a
few statements,
mostly procedure/function calls.
A procedure will end either normally or abnormally by sending an escape
message if an error occurs.
These errors will be trapped by using monitor groups and handled depending
on the situation.

@All
By the way did you know, that specifying RETURN is not neccessary to end an
procedure?
It just ends if the last statement is executed.

Birgitta

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Von: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]Im Auftrag von rob@xxxxxxxxx
Gesendet: Mittwoch, 3. August 2005 16:22
An: RPG programming on the AS400 / iSeries
Betreff: Re: AW: No Subroutines (was Re: Debugging many subprocedures)


Birgitta,

I disagree with "part" of this technique of the return subroutine.  The
part of a return subroutine for clean up purposes is valid.  The part of a
return subroutine to 'officially' only have one return point is as bad as
the people who used to code the following to get around shop edicts of NO
GOTOs!
C                1   CABEQ  1                                    MYTAG

Rob Berendt
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Dept 01.073
PO Box 2000
Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com





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Subject
AW: No Subroutines (was Re: Debugging many subprocedures)







>>Second, coding multiple returns in a routine CAN be a bad technique in
>>and of itself.  Multiple returns get to be problematic when you're
>>actually returning a value, and the value you return depends on which
>>point you're exiting from.  Even with a breakpoint on a P-E, it can be
>>difficult to tell what is actually being returned.  And if the calling
>>routine is not placing the value into a temporary value but instead
>>using it as a parameter to another routine (possibly one for which you
>>have no source), or worse yet returning the value to ITS caller, the
>>code can get difficult to debug.

That's why we decided to add a Return-Subroutine in almost each of our
procedure,
like we've done it already in our RPGIII programs.
In the Return-Subroutine, the return values, output parameters
and error handling (sending an excape message if an error occured) are
handled.

Example:
Monitor;
  If ParmXXX = *Blanks;
     Error   = True;
     MsgId   = 'MSG0001';
     exsr XReturn;
  EndIf;
  Chain MyKey MyFileF;
  If Not %Found;
     Error   = True;
     MsgId   = 'MSG0002';
     exsr XReturn;
  EndIf;
  ....
On-Error;
  $Error = True;
EndMon;

XReturn;

BegSR XReturn;
  If Error = True;
     If MsgId = *Blanks;
          MsgId  = 'CPF9898';
          MsgTxt = SDSMsgTxt;
     EndIf;
     SndEscMsg(MsgId: MsgTxt);
  EndIf;
  ParmOut1 = WhatEver;
  If %Parms  >= NbrParmOut2;
     ParmOut2 = MyFld;
  EndIf;
  Return MyRtnValue;
EndSR;

Birgitta


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