Path: utzoo!mnetor!uunet!husc6!mailrus!nrl-cmf!ames!pacbell!att-ih!ihnp4!inuxc!iuvax!pur-ee!uiucdcs!uxc.cso.uiuc.edu!uxe.cso.uiuc.edu!mcdonald
From: mcdonald@uxe.cso.uiuc.edu
Newsgroups: comp.lang.fortran
Subject: Re: recursion in general
Message-ID: <50500041@uxe.cso.uiuc.edu>
Date: 28 Mar 88 14:36:00 GMT
References: <531@a.UUCP>
Lines: 19
Nf-ID: #R:a.UUCP:531:uxe.cso.uiuc.edu:50500041:000:747
Nf-From: uxe.cso.uiuc.edu!mcdonald    Mar 28 08:36:00 1988



>We are extending Fortan for hypercubes and we have been rummaging around
>the standard some.  There seems to be no prohibition to recursion.

>The 1977 FORTRAN standard, ANSI x3.9-1978 says (page 15-1, lines 55-56):
>    "A subprogram must not reference itself, either directly or indirectly."

This is a restriction on CONFORMING PROGRAMS. It does not prevent writing
compilers that allow recursion. It just says that a program that uses
recursion is not required to work.

>Recursion is explicitly allowed in Fortran 8x.

When it is explicitly declared. My personal opinion is that it is good to
allow recursion, but also good to require it to be declared; it might
be that some machines run faster if recursion is prohibited.

Doug McDonald