> > Are you aware of such future changes in OCaml, that would lead to
> > incompatibility?

With the usual caveat that past performance is not an indicator of future
wealth...

In the last few years, the only change which caused a bit of an uproar was
camlp4 between 3.09 and 3.10 (which was totally incompatible but had the
same command name). This has all since resolved itself (camlp5 maintained
separately for developers who want the old mechanism and the new camlp4 now
in general use) but I think it's reasonable to say that the response to it
at the time means that it's unlikely that such a breaking change would be
introduced within the 3.x branch of OCaml in the future, but of course I too
don't speak for the guys at Inria. It seemed obvious from the list posts at
the time that 3.10.0 was adopted more slowly than normal minor
version-number releases because of the breaking change in camlp4.

Further history (looking only at Changes in the sources: I started using
OCaml at version 3.06, I think) suggests that breaking changes between major
versions have either been detectable and trivial to fix or aided with
translation tools. For example, stdlib function names had to change between
Caml Special Light 1.15 and Objective Caml 1.00 or new keywords between
OCaml 1.07 and 2.00 and between OCaml 2.04 and 3.00, there appears to have
been much concern for backwards compatibility with tools provided to help
the transition from various different previous versions of the merged
compilers.

As for what gems OCaml 4.x may or may not feature, you'd have to bribe the
priests at Inria for details of their dreams and wishes ;o)

> We intend to begin huge developments in OCaml (Web, GUI, system,...)
> and such changes will make our task a bit more difficult.

Your (valid) worry about future incompatibilities definitely shouldn't put
you off this! It's also painless to run multiple versions of OCaml
side-by-side (at least if building from sources).

HTH,


David