Re: Is Interfaces.Fortran Mandatory or Optional?

[John Harbaugh <johnh.s.harbaugh2@boeing.com>]

Robert A Duff wrote:
<snip> 
> See B.2(12,13).  There's no requirement to support interface to any
> particular language.  It would be silly -- suppose there's no Fortran
> compiler on some machine.  Is the Ada compiler vendor supposed to write
> a Fortran compiler?
>
B.2(12,13) is implementation advice, not a requirement.  It seems rather
obscure to conclude that an implementation, by not following the advice,
is free to provide any, some, or none of the children of Ada.  Too bad
the RM is not a forthright in this matter as it is say in the
dissallowal of decimal types.  
Besides, I thought the RM defined an interface to an ISO-conformant
object module.  This does not imply that the implementor provide
other-language compilers.  Is it not the case that C++ was not included
in Annex B because it is not yet an ISO standard?

> See also AARM-B.5(17.a), which points out the exact issue you're asking
> about.

        17.a   Ramification:  The means by which the Complex type is
provided in Interfaces.Fortran creates a dependence of
Interfaces.Fortran on Numerics.Generic_Complex_Types (see G.1.1).  This
dependence is intentional and unavoidable, if the Fortran-compatible
Complex type is to be useful in Ada code without duplicating facilities
defined elsewhere.

You're right, this does capture the issue.  It does not, IMHO, resolve
the issue.
> 
> A compiler might support interface to Fortran, and support just that
> portion of Annex G that is needed.  For example, it might support the
> Generic_Complex_Types thing, but disobey the strict accuracy
> requirements of Annex G.
> 
> But that's all just legalistic mumbo-jumbo.  If your machine supports
> Fortran (as many do ;-)), and you want it, then gripe at your Ada
> compiler vendor until they support interface to Fortran, and support it
> well.  In practise, it's not really an RM issue.
> 
> - Bob

Gripeingly yours (and thanks for your response),

	- John