Path: utzoo!mnetor!uunet!husc6!cmcl2!beta!a!jlg
From: jlg@a.UUCP (Jim Giles)
Newsgroups: comp.lang.fortran
Subject: Re: Recursion
Message-ID: <534@a.UUCP>
Date: 25 Mar 88 01:56:13 GMT
References: <7975@agate.BERKELEY.EDU> <533@a.UUCP>
Distribution: na
Organization: Los Alamos Natl Lab, Los Alamos, N.M.
Lines: 26
Summary: Some fundamental misunderstanding.


There seems to be a fundamental misunderstanding about what constitutes
a standard-conforming implementation of Fortran.  Two responses to the
issue of recursion have tried to claim that a processor which allows 
recursion is inherently not standard-conforming.  This is not true -
the standard explicitly allows for extensions.  Read ANSI X3.9-1978
FORTRAN 77 page 1-2 lines 25-43:

   A processor conforms to this standard if it executes standard-conforming
   programs in a manner that fulfills the interpretations prescribed
   herein.  A standard-conforming processor may allow additional forms
   and relationships provided that such additions do not conflict with 
   the standard forms and relationships.  [...]  Note that a standard-
   conforming _PROGRAM_ must not use any forms or relationships that 
   are prohibited by this standard, but a standard-conforming _PROCESSOR_
   may allow such forms and relationships if they do not change the 
   proper interpretation of a standard-conforming program. 

[My emphasis on _PROGRAM_ and _PROCESSOR_]

By the above description, a _PROGRAM_ which uses recursion is not 
standard-conforming, but a _PROCESSOR_ which allows recursion is
not against the standard.

J. Giles
Los Alamos