Excerpts from Paolo Donadeo's message of Thu Nov 22 00:21:43 +0100 2007:
> I'm fighting again with ocamlbuild. In the (excellent!) wiki I found
> two useful recipes: how to use findlib with ocamlbuild and how to
> compile source code using a syntax extension. Now it happens that I
> have both these needs, and I'm not so sure how to mix the ingredients
> and obtain a good dish.
> 
> At the moment the solution I have discovered (by trial and error)
> works well, but it doesn't seem very clean.
> 
> The involved files in my source directory are these:
> 
> ./xnuncc.ml
> ./myocamlbuild.ml
> ./ext_libs/openin-20070524/pa_openin.ml
> ./_tags
> 
> In xnuncc.ml I use the openin extension, and xnuncc.ml is the main
> compilation unit.
> 
> Here is the contents of _tags and the plugin for ocamlbuild:
> 
> ======= 8< CUT HERE: _tags >8 =======
> <dom> or <files> or <fragment_composer> or <test> or <doc> : include
> <ext_libs/openin-20070524> : include
> true : dtypes
> <**/pa_openin.ml> : camlp4of, use_camlp4of
> "xnuncc.ml" : camlp4o, use_openin
> ======= 8< END HERE: _tags >8 =======

<dom> (and many others) can be rewritten "dom" since it's constant.

[...]

> If I use "pa_openin.cmo", indeed, the result is an absurd (for me)
> error message starting with:
> 

[...]

In  a  "dep"  declaration  include  directories  are  not taken in account for
building pathnames.

> At the end of the story the question is: is this solution the best
> possible for compiling a project with findlib and a syntax extension
> present in a subdir of the project?

Not  yet  (you  can  still  factorise  the "ext_libs/openin-20070524" and even
compute it, since the plugin language is OCaml).

-- 
Nicolas Pouillard aka Ertai