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From: Mike Klein <mklein@alumni.caltech.edu>
Subject: Re: OO, C++, and something much better!
Date: 1997/02/19
Message-ID: <330B9703.219A@alumni.caltech.edu>#1/1
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William Clodius wrote:
> 
> Richard A. O'Keefe wrote:
> >
> > <snip>   However, in all of the languages I
> > mentioned, there is ***NO SEMANTIC DIFFERENCE*** between symbols that
> > may be used as operators and symbols that may not.  In Ada, "abs X"
> > involves the use of an operator.  In Fortran, "ABS(X)" involves the
> > use of a "function".  But the range of *semantic* possibilities is
> > *identical* for both languages.  <snip>
> 
> Minor quibble. I believe in Fortran 90, and possibly in some of the
> other languages, operators have additional semantic constraints that are
> not required by the language for functions in general, i.e., the
> corresponding function may not have certain obvious side effects such as
> modifying its arguments, SAVEd local variables, modifying global
> variables, etc. Side effects such as stack overflow, floating point
> exceptions, etc. are of course allowed as there is no practical means of
> preventing them. (Quibble on the quibble. While Fortran allows functions
> to nominally have side effects that are not allowed for operators its
> rules for expression evaluation makes reliance on the occurance of such
> side effects error prone. Well written production Fortran code should
> ideally only have functions that satisfy the semantics of operators.)
> 
Dont we already have terms for these concepts:

imperitive (called for side effects)
functional (no side effects, return value only)

Of course, most code is dysfunctional, but that's an other story :-)

Mike Klein
-- 
mailto:mklein@alumni.caltech.edu
http://www.alumni.caltech.edu/~mklein