Re: the need for speed

[Jon.Paris@xxxxxxxxxx]

 >> I came away from one of Jon's sessions at Common with the distinct
impression that every subroutine should be changed to a sub-procedure. I think I
heard him say that, but I probably misunderstood (as usual) what he was saying.

I think what I said (it is what I normally say anyway) is that I _personally_
don't bother with subroutines. For me they serve no useful purpose.
Subprocedures give me a natural language interface where the parameters are
clearly spelled out, local variables (most subroutines define at least some
'local' data), parameter validation, some facilities for automatic conversion of
parameter type/size, etc. etc. And subroutines give me ....... ?

The performance difference is so minimal as to not be worth considering. What
the IBM manual does not take into account is the overhead of 'parameter'
handling in subroutines. Most subroutines effectively use some data as
parameters. While an EXSR is faster than a subprocedure invocation, is it still
faster than moving three 20 character fields to fake out parameters? If it is
the difference I suspect will be small. Of course there are occasions when
performance needs are paramount, but I'll swap readability and maintainability
for performance most any day of the week.

If you believe that your subroutines do not use any 'parameters' then simply cut
that piece of code into a separate module, compile it and call it. If you can't
do this and have the resulting combo work - your subroutines were using
parameters <grin>

I do disagree with John Carr (think it was you John) on one point - I don't
believe that you should ever take the view that a coding style is acceptable
because the program will not be subject to future changes. Business changes too
fast to ever be able to make such a decision. I have programs in daily use that
I wrote 15 years ago that I was convinced would only be in use for 6 months or
so. There are also many examples of code that I thought would run forever ....
but we won't talk about what happened to them <g>


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