Re: [Caml-list] [ANN] Core Suite 111.17.00

[Yaron Minsky <yminsky@janestreet.com>]

We actually had a discussion about this internally, and I was mostly
convinced that my transition plan is the wrong one --- that it's
probably better to leave the old camlp4 based syntax extensions as
they are, and just mothball them; leave them around, but stop
improving them.  And then people who want to use the new and
better-supported extensions will need to flip to using ppx.  And you
can use the camlp4-based solution to straddle the gap if you need to
support both new and old compilers.

y

On Wed, Jun 18, 2014 at 8:57 AM, François Bobot <francois.bobot@cea.fr> wrote:
> On 18/06/2014 11:28, Yaron Minsky wrote:
>> This change isn't really part of that transition, but that transition will likely be necessary.  My
>> sense is that the right thing is to rewrite the syntax extensions using extension points, and then
>> write a shim camlp4 extension that converts "with sexp" to the correct annotation.  That said, this
>> is a long and tricky process that won't happen immediately on 4.02's release.
>
> Thank you for the quick answer. That seems the right transition path for the code of a project, but
> I wonder what happen at a bigger scale.
>
> After the transition projects will need to support older versions of ocaml that perhaps don't have
> extension points. Moreover every projects will not do the transition at the same time.
>
> It seems, IMHO, that type-conv will have to work for the following cases transparently:
>
> - camlp4 (with ocaml < 4.02 or >= 4.02) old syntax
> - camlp4 (with ocaml < 4.02 or >= 4.02) new syntax
>
> - extension point (with ocaml >= 4.02) new syntax
>
>
> Do you agree with that? Do you think it is doable/maintainable until ocaml < 4.02 are not used anymore?
>
>
> Best,
>
> --
> François