[wg-windows] Interim solution for OPAM on Windows

David Allsopp dra-news at metastack.com
Wed Sep 16 10:08:34 BST 2015

Mr. Herr wrote:
> On 16.09.2015 09:45, David Allsopp wrote:
> > Jonathan Protzenko wrote:
> >> David's email reminded me that I forgot to tell the world about this
> >> horrible hack that I did a while ago.
> >>
> >> http://protz.github.io/ocaml-installer/ now offers an installer with
> >> The toolchain is the usual one (native compilers / generating native
> >> windows programs / using mingw64 32-bit compilers). However, the
> >> installer now installs an "opam" program in c:\ocaml\bin. The opam
> >> program is a *cygwin 32-bit binary*, so it only works within a cygwin
> 32-bit terminal.
> >> I got as far as doing "opam init" and "opam install a-whole-bunch-of-
> >> packages", including mezzo and all its dependencies, batteries, and a
> >> couple others.
> >>
> >> All in all, I hope it'll provide a good enough interim solution until
> >> David finishes everything and I can, eventually, retire my installer
> :).
> > It's not (necessarily) the case that the installer would want retiring
> (but it may well change shape, especially where installing Cygwin is
> concerned). OPAM expects the system already to have an OCaml compiler
> (usually installed by the operating system's package manager) - one of the
> minor changes I have yet to make is to relax this requirement for OPAM on
> Windows, as it is less reasonable.
> Opam has an ocaml-less install procedure, see list "ocaml_beginners"::[]
> Conflicting installation advice" 16.08.2015 14:09 CEST, and
> http://opam.ocaml.org/doc/Install.html "Binary Installer".

I'm aware of that - however, if you forget to specify --comp, I'm fairly certain you get an exception at the moment (it certainly did when I last looked)...

> > However, the existence of the "system" switch means I was imagining that
> there would still want to be an installer which installs OCaml (and OPAM)
> "for all users". Apart from anything else, it would improve the first-time
> OCaml user's experience as installing OPAM on a system without OCaml must
> necessarily add a 10 minute or so delay while OPAM builds OCaml.
> >
> There is no system distribution in Windows, right? So opam must do it, and
> it does it well on *nix.

Yes there is - anything you install at a system level (i.e. for all users) is the "system distribution". That said, "system", as far as OPAM is concerned, simply means an OCaml compiler that it found in PATH.

> With all the progress opam has made and brought, a general scripting setup
> like perl / tcl / python is still lacking IMO, it would make ocaml more
> accessible for ad hoc scripting.

I'm not sure what you mean here?


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