Re: [Caml-list] syntax extensions with ocamlfind

[Maxence Guesdon <Maxence.Guesdon@inria.fr>]

On Mon, 2 Mar 2015 18:07:40 +0000
Andreas Hauptmann <andreas@ml.ignorelist.com> wrote:

> On Mon, 2 Mar 2015 18:48:46 +0100
> Maxence Guesdon wrote:
> 
> > It seems that ocamlfind only supports camlp4 for preprocessors. Am I
> > right ? Does anybody known how to achieve this ?
> 
> Take a look at the META file of camlp5. If i remember right, it achieves
> similar without native support inside ocamlfind.

Indded, thanks. But it seems that ocamlfind can handle only one
preprocessor, instead of building a command chaining the preprocessors.
When I have more than one packages defining a preprocessor, I get:

  ocamlfind: Several packages are selected that specify preprocessors:
  package camlp4 defines `camlp4', package mypkg.syntax defines
  `./mypp'

And the use of a preprocessor depends on having a "archive" variable
defined like that:
  archive(syntax,preprocessor,dynamow) = "..."

Which must not be empty to make the preprocessor used. If it's empty,
then I get:

  ocamlfind: Using -syntax, but no package is selected specifying a
  preprocessor as required for -syntax

Moreover, ocamlfind automatically adds a -I option to the preprocessor
command, in my case I end up with
  
  -pp "mypp '-I' '/home/guesdon/.opam/4.02.1/lib/mypkg'

So the preprocessor machinery seems very camlp{4,5} oriented.

I think I'll just require the user to add -pp "ocamlfind mypkg/mypp" on
command line option.

Maxence