From: Ethan Beyak <ethanbeyak@gmail.com>
To: janus@gcc.gnu.org
Cc: fortran@gcc.gnu.org
Subject: Re: Assignment interfaces with allocatable polymorphic variables in gfortran 5.5.0 & 8.1.0.
Date: Fri, 07 Sep 2018 14:36:00 -0000 [thread overview]
Message-ID: <CAJ3BazeOJ_bn9jgYPQJeDPW9QLSUH6OCrXKGnC6KvZOq2Jt8tQ@mail.gmail.com> (raw)
In-Reply-To: <CAKwh3qizC08Lfog0Pvd9ybamDmHf5wFFwtresjD6Dwu1cEGkKw@mail.gmail.com>
Janus,
Thank you very much for your response. I didn't realize you could put an
'assignment (=)' in a public statement. This'll solve my problem perfectly!
As a follow-up, let's say I did have multiple 'interface assignment (=)'
blocks in this module. Would the 'public assignment (=)' statement then
make all of assignments public then?
Is there any way to make these 'public assignment (=)' statements distinct?
I tried the following, both failed to compile on gfortran 5.5.0:
=======
interface assign_foo assignment (=)
module procedure foo
end interface assign_foo assignment (=)
interface assignment (=) assign_foo
module procedure foo
end interface assignment (=) assign_foo
'Error: Syntax error: Trailing garbage in INTERFACE statement'
=======
Is there any way I could apply the public attribute to the interface block
directly, or am I limited to public statements for affecting the
accessibility of interface blocks?
And a brief convention question: is it standard to omit whitespace between
'assignment' and '(=)' when writing Fortran, or is there no general
consensus?
Thanks,
Ethan
On Fri, Sep 7, 2018 at 5:56 AM Janus Weil <janus@gcc.gnu.org> wrote:
> Hi Ethan,
>
> > However, on version 5.5, I get the following errors:
> >
> > OUTPUT 2
> > =========
> > $ gfortran --version
> > GNU Fortran (Ubuntu 5.5.0-12ubuntu1) 5.5.0 20171010
> >
> > $ gfortran baz_module.f90 test_public_assignment.f90 -o test.out
> > test_public_assignment.f90:13:0:
> >
> > wrk = e ! invoking foo
> > 1
> > Error: Assignment to an allocatable polymorphic variable at (1) is not
> yet
> > supported
> > test_public_assignment.f90:19:0:
>
> Note that gfortran version 7 can also compile the program in its
> original form (so you don't necessarily need version 8), but
> unfortunately earlier versions fail.
>
>
> > Now I did find some workaround by setting the default accessibility of
> the
> > module to be public and explicitly declaring the complement of the set of
> > procedures and variables that I wanted to be private. I'm not sure what
> > gfortran 5.5.0 is doing to be honest, but the definition of the
> assignment
> > can be used in the calling program. Commenting out lines 5,6 and
> commenting
> > in lines 8,9 in baz_module.f90 gave me the following output on gfortran
> > 5.5.0
> >
> > OUTPUT 3
> > =========
> > Compiler version: GCC version 5.5.0 20171010
> > Compiler options: -mtune=generic -march=x86-64
> > d: 4.00000000 2.00000000 1.00000000
> > e: 8.00000000 6.00000000 4.00000000
> > f: 32.0000000 18.0000000 8.00000000
> > =========
> >
> > So I have two questions for the gfortran community: 1) do you know why
> > inverting the module accessibility causes these assignments to work in
> > gfortran 5.5.0? It seems as if the assignment interface was made public
> > somehow, but I'm not certain.
>
> Exactly, the "public" statement makes everything in the module public
> by default. The assignment operator is private otherwise.
>
>
> > 2) can you think of any *clean* solutions to
> > this problem? I'd love backward compatibility while not going against the
> > recommended standard of private default accessibility.
>
> A more reasonable approach might be to not make everything public, but
> just the assignment interface:
>
> public assignment(=)
>
> HTH,
> Janus
>
next prev parent reply other threads:[~2018-09-07 14:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-06 20:18 Ethan Beyak
2018-09-07 5:56 ` Janus Weil
2018-09-07 14:36 ` Ethan Beyak [this message]
2018-09-07 17:20 ` Janus Weil
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