RPG Program Source Code – Clever or Clear?

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August 8, 2017

RPG Program Source Code – Clever or Clear?

By NickLitten

August 8, 2017

RPG, clear, clever, programming, snippet, source, standards, style

Should RPG code be long form or short form?

I’ve been working on an interesting project focused on taking some old RPG code and re-factoring it to make it more efficient. Fascinating work for a client that is focused on doubling its IBM i throughput and reducing the CPU load of all its old programs.

This has frequently made me choose between writing a single line of %BIF’d up code that looks slick and minimalist – or – using clear RPG programming standards aka: writing multiple lines of code that are more readable and arguably (marginally) less efficient.

/me remembers the AS400 “SETON vs MOVEL *ON” arguments of yesteryear with a fond smile…

My official position on this: I prefer code readability over specialized (aka clever!) techniques.

I would rather write code that is a little more verbose, and well commented rather than do the same thing in a cryptic or obfuscated manner.

I just had to decipher this RPGLE line of code, because it was just too long and verbose but with no comments whatsoever:

BackDoorExtns = %Trim(BackDoorExtns) + 'CEL' + '000' + %Char(%len(%Trim(cleanCellNumber))) + %char(%DEC(cleanCellNumber:MoreCellPrec:MoreCellDec)) ;

This line of code basically receves an incoming cellphone, from a JSON webservice input, and converts to numeric (with the %DEC BIF) and then puts it in this string (backdoorExtns) but this line of code will BOMB if the cleanCellNumber variable has alphameric values so I changed it to:

Rpg code snippet clear rpg programming standards//Calculate cellphone number (morecell) and wrap in string with "CEL" control code at start
// JSON inputs the cellphone in incoming character field "cleanCellNumber" but if
// its actually dirty/non-numeric then set to *ZERO
monitor; 
   morecell = %DEC(cleanCellNumber:MoreCellPrec:MoreCellDec); 
   EvalR MskLen = '000' + %Char(%len(%Trim(cleanCellNumber)));
   BackDoorExtns = %Trim(BackDoorExtns) + 
                  'CEL' + MskLen + %char(morecell) ; 
   updateThisReservation = *on; 
on-error 105; 
    morecell = 0; 
endmon;

Yes, I’m guilty of waffling in my comments and sometimes using variable names that make me smile:

If WhiskyEmpty;
  TimeforBed();
endif;

Remember, Software undergoes beta testing just before it’s released.

Beta is Latin for “the program still doesn’t work”.

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