RE: [Caml-list] Interface(.mli) location

[David Allsopp <dra-news@metastack.com>]

moosotc@gmail.com wrote:
> David Allsopp <dra-news@metastack.com> writes:
> > moosotc@gmail.com wrote:
> >> Gabriel Scherer <gabriel.scherer@gmail.com> writes:
> >>
> >> > It is correct that ocamldep assumes that the .ml and .mli of a
> >> > given module are at the same place, but this is not the case for
> >> > the rest of the compilation chain, which is either concerned with
> >> > single source files (a .ml file or a .mli file) or with
> >> > "compilation units" (a .cmo and .cmi files passed together,
> >> > independently of where their source files were). In particular, all
> >> > type-checking tools do look in -I directories to find .cmi files
> >> > for the dependencies of the module being compiled (and at this stage
> they do not care for .mli files).
> >>
> >> But the script seems to (somewhat) contradict this, i.e. after
> >> `ocamlc -I d -c a.ml' ocamlc ignores the presence of .mli inside
> >> subdirectory d/, producing both .cmi/.cmo when when compiling a.ml.
> >
> > The -I option specifies extra directories for compiled files only, so
> > it's correct that the compiler ignores d/a.mli.
> 
> After sending the first post I've realized that: ocamlc -c d/a.mli was
> forgotten, but even after adding that to the script things do not change,
> i.e. following compilation of a.ml with -I d where d contains a.cmi still
> produces both a.cmo and a.cmi in the top-level directory.

Indeed - but that's the correct documented behaviour, even if not necessarily the ideal. There are various things you can do:

a) Delete ./a.cmi as part of your build procedure. This isn't ideal, though, because you lose the type-checking against d/a.cmi
b) Have an empty ./a.mli but never compile it - the compiler will then unify ./a.cmo against d/a.cmi. This isn't ideal because having a source file which you don't expect to compile will confuse dependency generators and automatic build rules.
c) Implement a new option in the compiler driver which suppresses the automatic generation of .cmi files (e.g. ocamlc -c -I d -no-cmi a.ml)


David