> How can I tell eclipse parser about my own camlp4 extension ?

For now, you can't. OcaIDE uses a custom parser written in Java,
copied from the rules of the original Ocaml parser. So, it only parses
standard syntax.
To parse a modified syntax, the file would first have to be processed
by camlp4.
But then, how would OcaIDE get the positions of the elements in the
original unprocessed file?

> How can I configure some "Run script" (typically a "make check" launched from
> eclipse), to test and debug my code ?

Custom makefile targets will be supported in a future version.

> I find that "format using camlp4" adds to much parenthesis, is it possible to do
> something about it (it is probably necessary to fine tune the camlp4 pretty printer ?)

I think you know a lot more about camlp4 than I, so I guess you're right.

> what is the correct way to use unison together with eclipse

I don't use unison, so I can't help you.

> No progress about the darcs incompatibility related to "linked URLs" used by OCaIDE
> and not supported by darcs eclipse.

I think this is more of a problem with darcs than with OcaIDE.


> I had two or three time a file opened where all modifications where in fact not
> performed on the filesystem (closing and reopening the file solved the problem).
> Is this a known bug with eclipse (I can not reproduce it yet) ?

Usually, this happens the other way around: the Eclipse workspace does
not reflect changes on the file system until you refresh your
workspace in Eclipse.