Re: [Caml-list] camlp4 & OCaml 4.08

["Richard W.M. Jones" <rich@annexia.org>]

On Sat, Jun 29, 2019 at 10:17:02AM +0000, David Allsopp wrote:
> > On 29 Jun 2019, at 10:44, Richard W.M. Jones <rich@annexia.org> wrote:
> > 
> >> On Sat, Jun 29, 2019 at 10:06:15AM +0100, Anil Madhavapeddy wrote:
> >>> On 27 Jun 2019, at 14:45, Richard W.M. Jones <rich@annexia.org> wrote:
> >>> 
> >>> 
> >>> I know camlp4 is dead and all that, but we've got some software which
> >>> still uses it.  I will probably port it to camlp5 when I have the
> >>> time, but has anyone got the patch to make camlp4 work with 4.08?
> >> 
> >> 
> >> To fork the thread slightly,  how big are the camlp4 dependencies remaining
> >> in your codebase, and is there anything we can do to help migrate?
> > 
> > The dependencies that I care about run through ocaml-gettext.  Gettext
> > is a specific method to make code internationalized and by its nature
> > it involves deep changes throughout our codebase, so porting away from
> > ocaml-gettext isn't an option any time soon.  However porting
> > ocaml-gettext to use something else might be.
> > 
> > ocaml-gettext has a tool which runs over the OCaml source code and
> > extracts the magic translatable strings, and it's my understanding
> > that this is the only reason it uses camlp4.  AIUI this cannot be done
> > using ppx's (maybe I'm wrong about that?) but could be done using
> > camlp5.  In fact it was me who did the original port of ocaml-gettext
> > from old camlp4 (ie. camlp5) to camlp4(!)
> 
> It’s not instantly clear to my (non-expert) eyes why this can’t be done with PPX. If I read the camlp4 script correctly, it doesn’t introduce any new syntax, it just matches on particular function calls and rewrites them?

Actually I believe it simply extracts the string parameters into a
separate file (from where they get translated).  However it's a
separate tool, it doesn't run as part of ordinary compilation.

Rich.

-- 
Richard Jones