Upgrading old source code — aka refactoring — is a fun past time and there are frequent little code snippets that I refactor over and over again. Some look similar but some look very different in modern language style. It’s perhaps worth documenting them in case someone else is trying to figure out alternative ways of refactoring old style RPG3 or RPG400 code. I frequently upgrade old RPG programs and ‘DO’ loops always get converted to RPGLE ‘FOR’ loops.
I just refactored an old RPG program that had a tasty little DO loop that looked like this:
C START DO END COUNT ... do lots of logic and stuff C ENDDO
This can be refactor to look like this:
RPG4 – also known as RPGLE /FreeFormat
For Count = Start to End; ... do lots of logic and stuff EndFor;
I prefer the syntax and layout of FOR loops – just more readable in my brain.
Plus we have some other nice and very readable techniques to control the count up and down. Lets say we wanted to count from 1 to 200 in steps of 5
for Count = 1 by 5 to 200;
or we can do that in reverse
for Count = 200 by 5 downto 1;