RE: New RPG programmers

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

> From: rob@xxxxxxxxx
> 
> Is SELECT unique to RPG?

RPG's SELECT is much more powerful than the C-based languages SWITCH
statement, which only allows an integer value.  That is, you can switch
on an integer, then execute a case based on a hard-coded value.  RPG's
WHEN statement is much more powerful, allowing you to go so far as to
execute external procedures to determine the case.  As far as I can
tell, VB's SELECT CASE is about halfway between; you can use other
types, but nowhere near as elegantly as RPG.

> Actually since I've started using SELECT I avoid IF's.

I often use SELECT instead of IF the same way you do, Rob, especially
when there's a chance that there might be more possibilities later.
It's also a nice way to force error checking.  Instead of:

IF this_cond
  DO This
ELSE
  DO That
ENDIF

I can write:

SELECT
  WHEN this_cond
    DO This
  WHEN that_cond
    DO That
  OTHER
    ERROR('Invalid condition')
ENDSL

ERROR throws an exception that ends the program, rather than waiting for
some unexpected error to occur later downstream.

Joe