(j3.2006) (SC22WG5.4362) Fwd: [ukfortran] WG5 informal ballot reInterop. TR

Bill Long longb
Wed Dec 1 14:36:14 EST 2010

On 12/1/10 8:58 AM, Aleksandar Donev wrote:
> Forgot the reply all for WG5, sorry...
> -------- Original Message --------
> Subject: 	Re: (j3.2006) (SC22WG5.4360) [ukfortran] WG5 informal ballot
> reInterop. TR
> Date: 	Wed, 01 Dec 2010 08:55:40 -0500
> From: 	Aleksandar Donev <donev at courant.nyu.edu>
> Reply-To: 	fortran standards email list for J3 <j3 at j3-fortran.org>
> To: 	fortran standards email list for J3 <j3 at j3-fortran.org>
> On 11/30/2010 10:11 PM, Malcolm Cohen wrote:
>>>  E) Re UTI 1: I do not like "unlimited polymorphic", and in fact
>>>  strongly prefer that it me made very clear assumed type has nothing to
>>>  do with unlimited polymorphic. But the standardese may need some more
>>>  work than I have time for.
>>  But it *is* unlimited polymorphic.

This discussion came up at the last meeting.  The problem that Aleks 
raises is that all discussion of polymorphic, and unlimited polymorphic, 
in the standard is in the section titled "CLASS".  And the operational 
sentence is:

"An entity declared with the CLASS(*) specifier is an unlimited 
polymorphic entity."

The proposal is, in effect, to add another sentence in the standard that 

"An entity declared with the TYPE(*) specifier is an unlimited 
polymorphic entity."

That opens a can of worms because the standard is littered with 
statements like "If MOLD is unlimited polymorphic ...".  In all of these 
cases, we mean something declared CLASS(*), and not something declared 
TYPE(*).  In other words, the current standard uses "unlimited 
polymorphic" as a synonym for "declared CLASS(*)".  The consequences are 
that (1) readers assume they are the same, and (2) going back and 
changing all of these statements to exclude TYPE(*) seems like more work 
that just avoiding the association of TYPE(*) with the term 'unlimited 
polymorphic' in the first place.


> Well, sure, since you have defined it. Perhaps that definition was fine
> when we only had CLASS(*). I am proposing that it ought to be changed
> now to *only* include CLASS(*), and TYPE(*) be separate. Polymorphic
> should mean an object that can have different dynamic types.
> Assumed-type objects should be classified as having no type. It is
> different from "has a type that I do not know at compile time". I know
> it requires more work to invent this new kind of untyped objected, but I
> think it is important,
> Aleks
> --
> Aleksandar Donev, Assistant Professor of Mathematics
> Courant Institute of Mathematical Sciences
> Office: 909 Warren Weaver Hall, New York University
> E-mail:donev at courant.nyu.edu
> Phone: (212) 992-7315; Fax: (212) 995-4121
> Mailing address: 251 Mercer St, New York, NY 10012
> Web:http://cims.nyu.edu/~donev
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Bill Long                                           longb at cray.com
Fortran Technical Support    &                 voice: 651-605-9024
Bioinformatics Software Development            fax:   651-605-9142
Cray Inc./Cray Plaza, Suite 210/380 Jackson St./St. Paul, MN 55101

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