Path: utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!unmvax!brainerd
From: brainerd@unmvax.unm.edu (Walt Brainerd)
Newsgroups: comp.lang.fortran
Subject: Re: Character aliases are Satanic extensions
Summary: Help is on the way
Message-ID: <87@unmvax.unm.edu>
Date: 12 May 89 22:53:59 GMT
References: <592@mbph.UUCP> <177@csun1.UUCP> <594@mbph.UUCP>
Organization: University of New Mexico at Albuquerque
Lines: 43

In article <594@mbph.UUCP>, hybl@mbph.UUCP (Albert Hybl  Dept of Biophysics  SM) writes:
> ...  The X3J3 committee scores
> a perfect 10.00 for allowing implementors to add his/her flag
> to their products.
> 
> : 	1.3.2. _Exclusions_.  This standard does not specify:
> : 	    [...]
> : 	  (4) The results when the rules of this standard fail
> : 	      to establish an interpretation.
> : and:
> : 	1.4. _Conformance_
> : 	  [...]
> : 	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.  [...]
> 
As usual, there are two sides to the coin.  These items have been
present in the Fortran standards from the beginning for very good reasons.
It allows implementors (not just IBM and DEC, but people doing all kinds
of experimental projects into which they want to embed Fortran) to add
things to the language and still be standard.  The standards committee
is attacked frequently for "inventing new stuff" (it usually is not put
this politely).  This extension scheme allows "new stuff" to be tried out
in real implementations providing a better chance of getting it right when
it is standardized.  Nice examples of extensions that didn't come primarily
from major vendors occurred in the multitude of preprocessors in the 1970s.
Their existence allowed me to argue (successfuly, of course) for putting
the IF...ELSE IF..ELSE.. END IF into Fortran 77.  Otherwise, it would not
be there now.

Of course, this puts the burden on the programmer to know what is
standard and what is portable, but vendors are getting a little better
about shading nonstandard things in their manuals.

To help balance things a bit, the proposed 8x says a processor must contain
"the ability to detect and report the use within a submitted program unit
of an additional form or relationship that is not permitted
by the numbered syntax rules or their constraints."  Also a processor
must have the capability of detecting obsolescent features.  How this is
done is _not_ specified; presumably it will be with a compiler option.