Path: utzoo!attcan!uunet!decwrl!sdd.hp.com!samsung!munnari.oz.au!goanna!ok
From: ok@goanna.cs.rmit.oz.au (Richard A. O'Keefe)
Newsgroups: comp.lang.misc
Subject: Re: Multi-compilers
Keywords: design, source
Message-ID: <3809@goanna.cs.rmit.oz.au>
Date: 24 Sep 90 09:08:15 GMT
References: <9009110403.AA03158@csd4.csd.uwm.edu> <2576@l.cc.purdue.edu> <2581@l.cc.purdue.edu>
Organization: Comp Sci, RMIT, Melbourne, Australia
Lines: 29

In article <2581@l.cc.purdue.edu>, cik@l.cc.purdue.edu (Herman Rubin) writes:
> Why is there an absolute value function rather than an absolute value
> operator?

In APL it's |x and in JOSS it's |x|.  abs was an operator in Algol 68 too;
how you entered it was of course system-dependent.

> I have used a dialect of Fortran which overloaded some of the "standard" functions,
> so that absolute value, logarithm, mod, etc., did not have to have any modifier
> indicating the type(s) of the arguments.  The compiler did the appropriate
> analysis.

Sounds like Fortran 77.  PL/I "GENERIC" functions provided this.  Algol 68
provided overloading for operators.  Fortran 90 provides user-definable
overloading.  It's in Ada.  Haskell overloads.

> A language is a set of macros to be interpreted by the compiler into machine
> procedures.  There is no good reason why the user should not be allowed to
> add macros in convenient notation to this list, nor why many of the restric-
> tions on the current macros need be there.

I strongly suspect that Pop-11 may have just what you want.  (Except that
for portability reasons it compiles to a common "Pop Virtual Machine".)
I suggest that you look in comp.lang.lisp for articles posted by Aaron
Sloman; he has recently pointed out that Pop-11 "syntax forms" let you
plant the code of your choice.

-- 
Heuer's Law:  Any feature is a bug unless it can be turned off.