Path: utzoo!attcan!uunet!decwrl!sdd.hp.com!hplabs!otter.hpl.hp.com!otter!phmb
From: phmb@otter.hpl.hp.com (Peter Brooks)
Newsgroups: comp.lang.pascal
Subject: Re: TP: Exponentiation?
Message-ID: <750001@otter.hpl.hp.com>
Date: 31 Jul 90 07:12:53 GMT
References: <950036@hpclapd.HP.COM>
Organization: Hewlett-Packard Laboratories, Bristol, UK.
Lines: 29

>In the new Extended Pascal standard (already approved by ANSI, IEEE, & BSR),
>the Pascal committee has added exponentiation to the language.  As a matter
>of fact, we added TWO operators.  We added "**" for raising things to
>real powers and "POW" for raising things to integer powers.

All well and good, but what if the result is complex? In order for the 
standard to be of use, Pascal ought to have a complex type and the 
above operators ought to return range/domain error if an attempt is
made to return a complex to a real.

In TP, the problem is compounded since the function will not return a
record, so even if you code a correct function returning you home
rolled complex record, it won't compile. I think that Borland is
encouraging you to either write a macro pre-processor to expand '**'
or '^' into in-line code before giving it to TP (not too difficult vide
software tools in Pascal) or to modify a global. I cannot believe that
any blue blooded Pascal adherent would feel anything other than
a chill of horror at the thought of modifying a global (or perhaps
a childhood memory of FORTRAN [child abuse of the mind]) so this 
must mean that Borland expects us to write macros. The question for 
Borland is then; where are the clips, stubs or hooks to allow us to
integrate our pre-processors into turbo.exe or tpc.exe?

My HP-28C happily returns the right result, changing into the complex
domain when required. The only little gripe is that it isn't possible to
set it to a mode where complex is the default ( why not hex, oct, dec,
real, complex ?).

Peter Brooks