Xref: utzoo comp.arch:4031 comp.lang.misc:1309
Path: utzoo!mnetor!uunet!husc6!ncar!gatech!purdue!i.cc.purdue.edu!k.cc.purdue.edu!l.cc.purdue.edu!cik
From: cik@l.cc.purdue.edu (Herman Rubin)
Newsgroups: comp.arch,comp.lang.misc
Subject: Re: FORTRAN Horror
Message-ID: <721@l.cc.purdue.edu>
Date: 24 Mar 88 11:18:03 GMT
References: <24861@yale-celray.yale.UUCP> <1135@pembina.UUCP> <800@cresswell.quintus.UUCP>
Organization: Purdue University Statistics Department
Lines: 40
Summary: But it takes forever to run!

In article <800@cresswell.quintus.UUCP>, ok@quintus.UUCP (Richard A. O'Keefe) writes:
> In article <10037@steinmetz.steinmetz.ge.com>, davidsen@steinmetz.steinmetz.ge.com (William E. Davidsen Jr) writes:
 ||   The arithmetic if is one of the few good things in FORTRAN
> ...
 ||   Of course I wouldn't suggest having it be implemented as goto's, but
 || some reasonable syntax, such as:
 || 	evaluate (fun(4,"test") < 22)
 || 	{ < 0 action }
 || 	{ equal action }
 || 	{ > 0 action }
> 
> What's wrong with
> 	typedef enum {LESS = -1, EQUAL = 0, GREATER = 1} Order;
> 	extern Order int_compare(int, int);
> 
> 	switch (int_compare(fun(4,"test"), 22) {
> 	    case LESS:    ...; break;
> 	    case EQUAL:   ...; break;
> 	    case GREATER: ...; break;
> 	}
> No new syntax needed.  Where something like this pays off is when
> you are comparing strings or complicated records, and you don't
> want to do it twice, but that is when you are defining your own
> comparison function anyway.  This is really a comp.lang.misc issue.

This is only acceptable if you are comparing _long_ strings or complicated
records; it is far too costly otherwise.  On the machines of the 50's, from
which the language gurus seem to have gotten their ideas, testing and
branching were cheap relative to computation; I fear that will never be the
case again.  

Subroutine calls are expensive; even though int_compare (and is the problem
only restricted to integers?) is not cheap, the subroutine call is likely to
be even more costly.  Few implementations allow the user to force inline.
The mind of the mathematician can conceive far more than the compiler can
fathom.
-- 
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907
Phone: (317)494-6054
hrubin@l.cc.purdue.edu (ARPA or UUCP) or hrubin@purccvm.bitnet