Projects including legacy files

[ivan-pi]

I've been trying to get fpm to work with some old-school packages like MINPACK: https://github.com/certik/minpack. These projects are generally just a bunch of fixed format ".f" files. For modern applications that rely on such legacy codes, an interface module is the first step towards safe function calls.

Trying to run fpm build on @certik's MINPACK fails with errors akin to:

fpm build --release
# gfortran (for build/gfortran_release/minpack/rwupdt.o build/gfortran_release/minpack/rwupdt.mod)
# gfortran (for build/gfortran_release/minpack/dmchar.o build/gfortran_release/minpack/dmchar.mod)
# gfortran (for build/gfortran_release/minpack/lmpar.o build/gfortran_release/minpack/lmpar.mod)
# gfortran (for build/gfortran_release/minpack/hybrd.o build/gfortran_release/minpack/hybrd.mod)
fpm: Error when running Shake build system:
  at want, called at src/Build.hs:205:11 in fpm-0.1.0.0-ExRRX9W2aflLvTBBChPpxh:Build
* Depends on: build/gfortran_release/minpack/libminpack.a
  at need, called at src/Build.hs:203:13 in fpm-0.1.0.0-ExRRX9W2aflLvTBBChPpxh:Build
* Depends on: build/gfortran_release/minpack/rwupdt.o
  at &%>, called at src/Build.hs:183:11 in fpm-0.1.0.0-ExRRX9W2aflLvTBBChPpxh:Build
* Depends on: build/gfortran_release/minpack/rwupdt.o build/gfortran_release/minpack/rwupdt.mod
  at error, called at src/Development/Shake/Internal/Rules/Files.hs:245:13 in shake-0.18.5-44KSA7uQF2VObxzEvLYZx:Development.Shake.Internal.Rules.Files
* Raised the exception:
Error, &%> rule failed to produce 1 file (out of 2)
  build/gfortran_release/minpack/rwupdt.o
  build/gfortran_release/minpack/rwupdt.mod - MISSING

I understand that fpm is expecting to find a module file for each single ".f" file. Is it possible to somehow work around this? The farthest I could get it in the fpm source was to remove to the "-Wimplicit-interface" flag which was creating lots of warnings 🙈 .

Am I right to think fpm is currently most suitable for projects composed of multiple module files?

[LKedward]

I was playing around with gtk-fortran and I found a work-around for non-module sources by renaming them to .in files so that fpm ignored them and including them with the include statement in a module.

It's not ideal and I'm not sure what the plan is for supporting non-module sources but I think they should be supported in some form.

Perhaps the larger question is whether we will make fpm flexible enough to support legacy packages in their original form or require restructuring of such packages; this latter option is not as extreme as it sounds since for some packages, fpm support will be brought through a third-party fork anyway (i.e. not via the upstream repo).

[everythingfunctional]

At the moment, fpm is only really targeted at projects with modules. At some point we may support non-module sources, but it may be some time before we get to it.

@LKedward , clever workaround. I may even suggest that as a recommended migration path.

In the mean time, there is always the out that fpm now supports custom build scripts or Makefiles (with some specific requirements).

[certik]

We have to support non-module sources. But this might be a feature to put into the Fortran based fpm to keep the Haskell based on minimal to be used in bootstrapping.