Re: ILE RPG:Is the use of ITER & LEAVE Structured Programmin

Frank,

Personally, I _DO_ think of ITER and LEAVE as structured programming ops. To me,
one of the primary benefits of structured code is readability of program logic, 
not that they perform similarly to non-structured ops like GOTO/TAG. 

As an example, Do loops are considered to be structured opcodes. Consider the 
following:
C             DOU        (FldXXX = 'A')
C             chain      xxxx             95
C  95         leave
C             .... 
C             ENDDO

This code performs the same as above but is unstructured:
C     LOOP1   TAG
C             CHAIN       xxxx            95
C  95         GOTO  EXIT1      
C             ....
C     FLDXXX  COMP  'A'                   96       (=)
C  96         GOTO  LOOP1       
C     EXIT1   TAG

I don't think it's fair to say that just because an opcode seems similar to 
GOTO/TAG that it is not "structured". I can't think of a single "structured" 
opcode that I could not simulate with various GOTO/TAG, COMP, etc.

This bring up another point. I have seen code written with "structured" ops that
were anything but structured.  This programmer refused to use use 
"nonstructured" opcodes and, IMO, he suffered greatly for it.  To me, structured
programming is as much a design issue as it is a coding issue. The goal is to 
produce code that is efficient and readable. 

Well, enough of that.... :) Gotta go.....

Eric A DeLong
ericadelong@pmsc.com

______________________________ Reply Separator _________________________________

     
     Hi Folks,
     
     I was just looking at a printout from the News400.com website about 
     RPG ILE (tips and techniques). I belive the text was authored by  
     Bryan Meyers. However he mentioned the use of ITER and LEAVE in the 
     context of structured programming. 
     
     I suppose I am a purist and I ensure that these opcodes are not part 
     of any new development that we produce. IMHO these opcodes are GOTO's 
     without TAGs and are not structured programming. I'd love to hear 
     other opinions on this. And what is a strict defination of Structured 
     programming.
     
     Regards,
     
     Frank Meaney.
     (Unisoft Systems Ltd)
     


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