Re: X-Spec (was: "RPG isn't cool")

[Mark Lazarus <mlazarus@xxxxxxxx>]

Hans,

At 01:11 PM 5/11/99 -0400, you wrote:

>Well, a month ago, I would have given the "X-Spec" 50-50 odds of
>making it into our next release.  Here's an update:  It's now
>called the "CF-Spec" or "Free-form Calculation Specification"
>and it's currently working in the lab!  Most of the code is
>already in place in the compiler.  Believe it or not, this
>enhancement turned out to be rather easy to code.

 This sounds exciting.

>1) IFxx, DOWxx, etc.  There are currently expression alternatives
>   for these, so why bother carrying these forward in the new
>   scheme.  Do we support these in the CF-Spec?  ie. Do we allow
>   code like:  " CF   ifeq counter 17 "?

>2) String ops:  SCAN, SUBST, XLATE, etc.  There are expression
>   or BIF alternatives (or will be) for most (possibly all) of
>   these.  Do we support these opcodes in the CF-Spec?

>3) Move ops:  MOVE, MOVEL.  You could code EVAL/EVALR for many
>   moves, but not all MOVEs are easily convertible to the EVAL
>   statement.  Do we support MOVEs in the CF-Spec?  (If not, we
>   would have to add additional new BIFs, which still wouldn't
>   cover all of MOVE semantics.)

>4) Arithmetic ops:  ADD, SUB, etc.  As many have already
>   discovered, arithmetic in expressions is not totally
>   compatible with arithmetic in the fixed opcodes.  Do we
>   support these in the CF-Spec?  ie.  Do we allow code
>   like:  " CF  add 1 counter "?

>So, the general issue is how much of the "old" stuff do we carry
>forward in the CF-Spec and how much can we leave behind?

 As you point out, there is functionality that will be lost (or at least
kludged) if full backward compatibility is not part of the spec, especially
for the MOVE and arithmetic op codes. I vote for keeping as much as is
practically possible.

 BTW, please post / publish the proposed syntax BEFORE it's "in the can."
Several of RPG IV's warts or shortcomings could easily have been avoided by
allowing the people in the trenches voice their opinions first.  This means
people outside of Common, too!

 -mark

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