(j3.2006) [Fwd: RE: Ada's Fortran interoperability AI]

[Van Snyder]

On Sun, 2017-03-05 at 14:36 +0000, John Reid wrote:
> 
> Van Snyder wrote:
> > The Ada standard has a Fortran interoperability annex that contains
> > significant mistakes.  Those ought to be corrected.  It also has an
> > annex each for C and COBOL interoperability.  Neither the Fortran nor
> > COBOL interoperability annex refers to the C interoperability annex.
> >
> > The 2012 Ada standard (reference manual), annotated reference manual,
> > and rationale, are online at
> >
> > http://www.adaic.org/ada-resources/standards/ada12/
> >
> > and perhaps elsewhere as well.
> >
> > If one wishes to recommend a different approach from the one in
> > AI12-0058 to remedy the deficiencies in the 2012 Fortran
> > interoperability annex, it ought to be submitted to WG9.  The current
> > chair is Joyce Tokar <tokar at pyrrhusoft.com>, but I'm sure Randy Brukardt
> > <randy at rrsoftware.com> would accept it.
> 
> We seem to be agreed that Steve's approach is the right one. Has anyone 
> passed that on to WG9? I have met Joyce at SC22 meetings and would be 
> happy to write to her.

I passed it along to Randy Brukardt.  He pointed out that Ada already
has a Fortran interoperability annex, and has had one since 1983.  They
will not remove it, and suggest that Ada users switch their existing
codes to use Fortran's C interoperability features by way of Ada's C
interoperability features.  AI12-0058 will change their Fortran
interoperability annex so as not to recommend that Fortran programs use
such things as REAL*4.

> 
> John.
> 
> 
> 
> >
> > On Tue, 2017-02-21 at 20:17 -0500, Steve Lionel wrote:
> >> I think this document is taking the wrong approach. Instead it should
> >> build on the C interop features. Indeed, if Ada can "look like C",
> >> then the Fortran standard C interop features can be used.
> >>
> >> I am especially troubled by the notion that an Ada and a Fortran
> >> implementation should "conspire" to support a shared interface for
> >> arrays, allocatables and such. We already have that in F2015 and
> >> several implementations of the C interop stuff exist.
> >>
> >> The stuff about kinds should instead refer to C types the way C
> >> interop does.
> >>
> >> Most important, any Fortran routine called by Ada must be
> >> interoperable (and any Ada procedure called by Fortran must be
> >> interoperable), so that one doesn't get into implementation specifics
> >> such as hidden arguments, calling mechanisms and name decoration.
> >>
> >> I assume Ada has a C interoperability specification. That should be
> >> usable with Fortran along with some guidance for the programmer.
> >>
> >> Steve
> >>
> >> On 2/21/2017 8:08 PM, Van Snyder wrote:
> >>
> >>> I mentioned at J3 meeting 212 that there is a proposal to amend Ada's
> >>> annex concerning Fortran interoperability to be compatible with Fortran
> >>> 2008, not to recommend things that were never part of any Fortran
> >>> standard, and not to recommend things that are processor dependent or
> >>> dependent upon processor command-line options used when compiling a
> >>> Fortran program.
> >>>
> >>> This resulted in generation of what WG9 calles an "AI" or "Ada Issue."
> >>>
> >>> Dan asked me to forward the AI.
> >>>
> >>> I asked Randy Brukardt, a denizen of WG9, to send it to me.
> >>>
> >>> It's attached.  From my perspective, it looks quite good.  Let me (or
> >>> Randy) know if you have comments on it.
> >>>
> >>> Van
> >>>
> >>> -------- Forwarded Message --------
> >>> From: Randy Brukardt <randy at rrsoftware.com>
> >>> Reply-to: <randy at rrsoftware.com>
> >>> To: Van.Snyder at jpl.nasa.gov
> >>> Subject: RE: Fortran interoperability AI
> >>> Date: Tue, 21 Feb 2017 16:07:14 -0600
> >>>
> >>> You can always get these out of our database (see
> >>> http://www.ada-auth.org/AI12-SUMMARY.HTML, looking for Fortran will find it
> >>> more quickly than asking me). I've attached the most recent version.
> >>>
> >>>                  Randy.
> >>>
> >>>> -----Original Message-----
> >>>> From: Van Snyder [mailto:Van.Snyder at jpl.nasa.gov]
> >>>> Sent: Tuesday, February 21, 2017 3:55 PM
> >>>> To: randy at rrsoftware.com
> >>>> Subject: RE: Fortran interoperability AI
> >>>>
> >>>> Randy:
> >>>>
> >>>> Can you send me a copy of the AI?  The Fortran committee
> >>>> asked me for it when I mentioned it in my liaison report last week.
> >>>>
> >>>> Thanks,
> >>>> Van
> >>>
> >>>
> >>> _______________________________________________
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> >>> J3 at mailman.j3-fortran.org
> >>> http://mailman.j3-fortran.org/mailman/listinfo/j3
> >>
> >>
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