Xref: utzoo comp.lang.fortran:717 comp.software-eng:612
Path: utzoo!dciem!nrcaer!scs!spl1!laidbak!att!pacbell!ames!killer!tness7!tness1!nuchat!sugar!ssd
From: ssd@sugar.UUCP (Scott Denham)
Newsgroups: comp.lang.fortran,comp.software-eng
Subject: Re: Fortran follies
Message-ID: <2082@sugar.UUCP>
Date: 4 Jun 88 06:34:27 GMT
Article-I.D.: sugar.2082
References: <5377@cup.portal.com> <2852@mmintl.UUCP> <1005@cresswell.quintus.UUCP>
Organization: Sugar Land UNIX - Houston, TX
Lines: 28
Summary: taking the "proper way" a step farther

In article <1005@cresswell.quintus.UUCP>, ok@quintus.UUCP (Richard A. O'Keefe) writes:
> In article <2852@mmintl.UUCP>, franka@mmintl.UUCP (Frank Adams) writes:
> > In article <5377@cup.portal.com> Paul_L_Schauble@cup.portal.com writes:
> > I would recommend that you regard a dimension of 1 for an argument as
> > meaning that the dimension is undefined.  It's not pretty, but it works.
> This has never been strictly legal.  Fortran 77, unless I am much mistaken,
> has a "proper" way of doing it:  the last (and only the last) dimension of
> a formal array parameter may be '*'.  So this declaration should read
> 	real a(*), b(*)
> A Fortran compiler is entitled to generate code to check the actual
> subscripts against the declared dimensions.

 Agreed, the RIGHT way to do it in '77 is to use the * - I've always 
disliked the use of anything other than a variable or a * for a dummy
array as it implies information (true array extent) that's very often
not true. A Fortran compiler certainly IS entitled to do run-time sub-
script checking, but I'd hate to see what the impact would be on a real
set of production codes using a high level of subroutine nesting. It's
a great thing to have during development and debugging but it's just not
realistic in many environments.  In the case that subscript checking is
NOT being done, than the best thing the compiler designer can do for the
user is assume that the last (and only the last) dimension of ANY 
array received as an argument is in fact unknown, be it specified as 1,
100, ISIZE, or *. Why break existing code if you can avoid it ???
  
    Scott S. Denham 
    Western Atlas International
    Houston, TX