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

[moosotc@gmail.com]

David Allsopp <dra-news@metastack.com> writes:

> moosotc@gmail.com wrote:
>> David Allsopp <dra-news@metastack.com> writes:
>> 
>> > moosotc@gmail.com wrote:
>> >> moosotc@gmail.com writes:
>> >>
>> >> > moosotc@gmail.com writes:
>> >> >
>> >> >> David Allsopp <dra-news@metastack.com> writes:
>> >> >>
>> >> > [..snip..]
>> >> >
>> >> >>>>
>> >> >>>> d) Make the compiler skip generation of .cmi if it sees one in the
>> -I
>> >> >>>>    directories?
>> >> >>>
>> >> >>> No - I think the use-case is too niche to justify breaking
>> >> >>> backwards compatibility. That's potentially a very subtle way to
>> >> >>> break someone else's existing build system. The existing
>> >> >>> behaviour is precisely documented in the manual (even if it's not
>> >> >>> necessarily the best approach).
>> >> >>>
>> >> >>
>> >> >> Original post asked for either change of behavior or
>> >> >> documentation, I failed to find the precise documentation, care
>> >> >> pointing out where exactly things are described in the manual?
>> >
>> > http://caml.inria.fr/pub/docs/manual-ocaml/comp.html#sec263 describes
>> > how .mli and .ml are handled by the compiler (and when .cmi is
>> > generated or checked against) and the description of -I in
>> > http://caml.inria.fr/pub/docs/manual-ocaml/comp.html#sec264 explains
>> > that -I only adds search directories for compiled files, not source
>> > files.
>> 
>> Thanks, but the manual is completely silent on WHERE it looks for those
>> files. The issue is not trivial as there are 3 options I can readily come
>> up with:
>>      a. current working directory
>>      b. base directory of -o argument
>>      c. a set of -I directories
>>      d. directory where file to be compiled lives
>> 
>> It looks as if option d. is in effect, but nowhere it is spelled out.
>
> Hmm - to my taste the silence says everything required! Options b and
> c are completely illogical (b would involve inferring an input
> directory from an output directory and option c contradicts something
> the manual does state about what -I means). Option a would be
> surprising behaviour and to my mind is contradicted by the use of "x"
> in italics 8.1 which to me quite reasonably reads as "change the .ml
> to .mli" and so include the directory, if there is one. To expect the
> compiler to look for ./foo.mli when you specified bar/foo.ml would
> mean you'd changed "x".
>

As outlined in the original message, suppose you have the same interface
but several different implementations (selected during the package
configuration step for instance), let's call the module Mod.

Under option d. variants (living in different directories) would each
have to carry the _same_ mod.mli file in the container directory just to
satisfy the compilers discovery logic.

srctree/var1/mod.{ml,mli}
srctree/var2/mod.{ml,mli}

instead of potential

srctree/mod.mli srctree/var1/mod.ml srctree/var2/mod.ml

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