Re: trimming non-numerics

[Hans Boldt <boldt@xxxxxxxxxx>]

Bob Cozzi wrote:
> Hans,
> I do remember Dick Bains complaining when they implemented XLATE in RPGIII
> as to how poorly it performed. So %SCAN over and over again would be faster?
> Hmmm, maybe going further and using memchr() would even be better?
> -Bob

Bob: If you're concerned about performance, then you need to do some 
performance testing on the alternatives, using representative samples of 
expected data. But in this case, comparing the performance of XLATE in 
RPG III versus XLATE or %XLATE in RPG IV is meaningless.

At any rate, when the "from" or "to" argument of %XLATE is a variable, 
generally, RPG IV dynamically builds a translate table which is used to 
perform the translation. So, you're performing several loops over the 
operands.

Perhaps using XLATE (or %XLATE) might be better than using %SCAN within 
the filter loop for certain classes of date, perhaps not. But which you 
choose depends on lots of different (possibly conflicting) factors. If 
performance is important, then you might choose one particular 
implementation after lots of rigorous performance testing on 
representative data (worst case, best case, average case, etc.). If 
readability and maintainability of the code is important, then a 
different implementation may be more appropriate.

Anyways, I still stand by my recommendations. I think it's easier to 
maintain, and my gut tells me it's probably faster than using XLATE. And 
even if it isn't faster, the difference probably isn't worth fretting over.

Cheers! Hans