Path: utzoo!mnetor!uunet!husc6!bbn!gatech!hubcap!fpst
From: fpst@hubcap.UUCP (Steve Stevenson)
Newsgroups: comp.lang.fortran
Subject: Re: Fortran 8x, recursive procedures
Message-ID: <1180@hubcap.UUCP>
Date: 23 Mar 88 13:11:37 GMT
References: <522@a.UUCP>
Distribution: na
Organization: Clemson University, Clemson, SC
Lines: 31

in article <522@a.UUCP>, jlg@a.UUCP (Jim Giles) says:
> 
> 
> There are a number of Fortran environments that already allow recursive
> subroutines and/or functions.  The addition of recursion is something
> that is long overdue.  Efficient implementations of any given algorithm
> will probably remain iterative, but recursion is often the most natural
> presentation of an algorithm and should be provided (if only to allow
> quick testing of ideas).
> 

We are extending Fortan for hypercubes and we have been rummaging around
the standard some.  There seems to be no prohibition to recursion.  As
you point out, there are several.

The problems seems to be that, as usual, the last used compiler becomes
the standard definition.  Since folks weren't required to support
recursion, they didn't.  The rules as to what is local data variables
to a procedure and what are not is quite clear.  The inefficiencies
are runtime stack inefficiencies [ if multiple copies of the activation
record are inefficiencies.]

The obvious problem is that those holding that all computers look
like the IBM 709x and therefore Fortran 77 is an adequate model need
to be re-educated.

-- 
Steve Stevenson                            fpst@hubcap.clemson.edu
(aka D. E. Stevenson),                     fpst@clemson.csnet
Department of Computer Science,            comp.parallel
Clemson University, Clemson, SC 29634-1906 (803)656-5880.mabell