"If %scan(x:y)" is not valid???

["Jon Paris" <Jon.Paris@xxxxxxxxxxxxxx>]

 >> No matter which one I use, I'm still going to look at the %scan (or
%check) expression to determine what it's doing.  Why hide it somewhere else
in the source?

The whole point is that you _don't_ have to go look at it.  The subroutine
approach forces you to look at the code because the subroutine can and often
does touch any and every variable in the program.  The subprocedure as a
minimum _tells_ you that it is processing the parameter that is passed and
if you are not interested in the specifics you don't have to waste time
looking at the code.  If the code has a reasonable discipline to it, it
shouldn't be touching/updating anything in the global section.

The comparison I sometimes make with students is that when you see a CHAIN
or a READ op-code in a source you don't go trying to trace the code path of
IBM's stuff (well some folks do <g>) - you TRUST it to do what it says it
will given the parameters (factors) that you passed to it.  Why should your
code be any different?  If the routine is well named etc. why on earth would
you ever go looking at the code?  We have all learnt the hard way that
subroutines can't be trusted - it's time to do things differently.  As I
love pointing out to managers who are reluctant to change - one definition
of insanity is to keep doing the same thing over and over and expect
different results.  We've built RPG apps the same way for years and still
the backlog grows - isn't it time to try something different (and no I don't
mean Java!!)


Jon Paris
Partner400