Re: [Caml-list] Why should I use .mli files?

[Oliver Bandel <oliver@first.in-berlin.de>]

Am 30.10.2012 um 16:52 schrieb Didier Cassirame <didier.cassirame@gmail.com>:

> 
> Thinking about it, there's at least one case where mli files are not so useful: When you have several modules which must all comply with a certain module type. In that case, all the mli files would be identical, and a modification of the module type would necessitate to change all the .mli.

Sounds like you reformulated an advantagenas being a disadvantage.
If someone changes a type of a module by accident, it,will pop up as
problem.
Also I wonder, if a type that is used by other modules
might not also need to change the mplementation.

I think it depends on the kind of change.

Maybe you can provide an example.


Somehow the discussion looks a bit like
changing the interface often to be a sport
for programmers.
I remember times, when it was a good idea tomchange interfaces
as seldom as possible.
But modern times bring modern behaviour.

Maybe soon there will be a fast-interface-change contest.

One big advantage of mli-files is, to carve the interface in stone.

So even I mostly used OCaml only for my own small projects,
in a big project with many developers, it would make sense
that the team will plan the interface, and when the decisionis done,
the project leader or a certain person who is responsible for
mantaining the nterfaces, will create the file and has
rw-permissions, and the other developers only have group-readability.
So then they have to use the interface as it was agreed upon.

And the one who wants to implement furthe things can omit the mli file for a while,
but if the code does not compile with the official mli-file,
the code will be rejected.

I think this is a valuable tool, the mli can provide clear interfaces,
and this is working well wirh many developers.
And if changing of intefcüace really can't be avoided,
it will need a team meeting on intercace change.

Thats totally different to lets-change-they-interface-as-often-as-possible
contest behaviour.


Best wishes,
    Oliver