Re: Fortran file naming

[Rik]

On 11/24/2014 09:14 AM, Ben Abbott wrote:
>> On Nov 24, 2014, at 11:31 AM, Rik <address@hidden> wrote:
>>
>> On 11/24/2014 07:57 AM, John W. Eaton wrote:
>>> On 11/23/2014 09:24 PM, Rik wrote:
>>>> All,
>>>>
>>>> I'm cleaning up configure.ac a bit and I came across this:
>>>>
>>>> FC=$F77
>>>> AC_SUBST(FC)
>>>>
>>>> which makes FC an alias for F77 in Makefiles.  However, all of the Makefile
>>>> rules I see use $F77.  Is there something I'm missing or can we delete this
>>>> as cruft?
>>>>
>>>> Just to test, I commented out the two lines in configure.ac and re-built
>>>> Octave and there were no issues.
>>> There are a number of places where FC appears, so you'll need to fix
>>> those if you eliminate the substitution.
>> I could only find 3 independent instances in the Mercurial tree.
>>
>> Aliasing FC to $F77
>> configure.ac:707:FC=$F77
>> configure.ac:708:AC_SUBST(FC)
>>
>> Adding the alias into the Makefiles
>> build-aux/common.mk:94:FC = @FC@
>> build-aux/common.mk:557:  -e "s|%OCTAVE_CONF_FC%|\"${FC}\"|" \
>>
>> In README.MacOS
>> etc/README.MacOS:157:  export FC="/usr/bin/gfortran"
>> etc/README.MacOS:178:  export FC="/usr/bin/gfortran"
>> etc/README.MacOS:394:  export FC=/opt/local/bin/gfortran-mp-4.4
>>
>> My test of commenting out the configure.ac would have taken care of the
>> first two.  I don't know anything about compiling on MacOS.  Could someone
>> on a Mac platform comment out lines 707, 708 of configure.ac and then run
>> the entire build cycle to see if it is successful:
>> ./bootstrap
>> ./configure
>> make
>>
>>> Maybe it would be best to use FC consistently instead of F77, including
>>> using the AC_PROG_FC macro instead of F77?  I'm not sure of the
>>> implications though.
>> AC_PROG_F77 tries to find a compiler that is Fortran 77 compliant, while
>> AC_PROG_FC tries to find the most modern Fortran compiler available
>> (Fortran 95, Fortran 90).  I think if the code base that we have is written
>> to be compliant with Fortran 77 then we are correct in using AC_PROG_F77.
>>
>>> So another option is to leave things alone as they seem to be working.
>> I'm motivated to get this right because the Autoconf tools are so baffling
>> to most people that everyone shrinks from having to modify anything in
>> them.  This, in turn, allows a lot of cruft to build up which then makes
>> the files even more difficult to understand and modify--a positive feedback
>> loop leading to a negative outcome.
>>
>> --Rik
> I'd prefer to rename all the f77 files to use the *.for suffix, and then do 
> away with the F77 variable.
>
> That way f77, f90, f95, f2003, etc wlll all work.  Are there any legacy 
> systems, which Octave is able to build on, that do not include gfortran as 
> part of gcc?

Why do we need to rename the existing F77 files?  gfortran interprets
anything ending in .f as fixed format, usually F77, code.  Or is this a
move to potentially use other compilers which do not have this convention?

--Rik