Re: subroutines are bug factories was: Classic Traps -- I need yourinput!

"Francis Lapeyre" wrote:

Actually, in my opinion, it's the local variables that make code more
bug-prone. Why on earth do I need to keep track of what the variable is in
this or that procedure, anyway?

Francis -
I have to disagree strongly - and this is not my opinion, it is based on the
theories of experts much more knowledgeable than me.

I was taught in structured programming classes that low coupling (in this
case, exemplified by using subprocedures with local variables) is much
preferred over high coupling (using global variables to pass values to
subroutines).

See:
http://en.wikipedia.org/wiki/Coupling_(computer_science)

Think about the number of times you have debugged a program where one
subroutine clobbered the value of a variable that was vital to another
subroutine and caused the program to malfunction. From the beginning as an
RPG programmer, I hated the fact that all variables in an RPG program were
global.

IMO, It was very nice to see the implementation of local variables in RPGIV
subprocedures.


Please repeat after me:
low coupling, high cohesion!
Low Coupling, High Cohesion!
LOW Coupling, HIGH Cohesion!

Regards,
sjl