Re: [Caml-list] Setting up OPAM in emacs

[Leo White <lpw25@cam.ac.uk>]

My personal solution for Tuareg mode is to put:

  ;; Use OPAM's ocaml
  (setq tuareg-interactive-program "opam config exec ocaml")

in my .emacs.

Regards,

Leo

Wojciech Meyer <wojciech.meyer@gmail.com> writes:

> Christophe's function hook is probably much better and elegant solution,
> but this works for me:
>
>>>
> (defun dm-opam-switch-root (ocaml-version opam-root)
>   (interactive "sOCaml version: \nsOPAM root: ")
>   (let* ((path (if (string-match "\\.opam" (car exec-path)) (cdr exec-path) exec-path))
>          (entry
>           (replace-regexp-in-string
>            "\n" ""
>            (shell-command-to-string
>             (format "opam switch --root %s %s > /dev/null && opam config env | sed -n 's/^PATH=\\([^:]\\+\\):.*$/\\1/p'" opam-root ocaml-version))))
>          (env-path (replace-regexp-in-string "\n" "" (shell-command-to-string (format "opam config env --root %s | sed -n 's/^PATH=\\(.*\\)/\\1/p'" opam-root)))))
>     (setq exec-path (cons entry path))
>     (setenv "PATH" env-path)))
>
> (defun dm-opam-switch (ocaml-version)
>   (interactive "sOCaml version: ")
>   (dm-opam-switch-root ocaml-version "~/.opam"))
> <<
>
> I wouldn't say myself it's a perfect script, but it works. Note that I
> use a lot of shell trickery instead of Emacs buffers, which is probably
> not a good idea.
>
> You just say M-x dm-opam-switch, and indicate which version you would
> like.
>
> Best,
> Wojciech
>
> Christophe TROESTLER <Christophe.Troestler@umons.ac.be> writes:
>
>> On Tue, 28 May 2013 09:59:53 +0400, Ivan Gotovchits wrote:
>>>
>>> 2. Use «eval `opam env config`» in the begining of a compile-command.
>>>    This works fine when you switch compiler, but other commands, such as
>>>    «C-c C-s» doesn't use new environment.
>>
>> I use this for the compilation:
>>
>>     ;; OPAM compilation — one must update to the current compiler
>>     ;; before launching the compilation.
>>     (defadvice compile (before compile-opam activate)
>>       "Run opam to update environment variables"
>>       (set (make-local-variable 'compilation-environment)
>> 	   (with-temp-buffer
>> 	     (ignore-errors (call-process "opam" nil t nil "config" "-env"))
>> 	     (goto-char (point-min))
>> 	     (while (re-search-forward "; *export.*$" nil t)
>> 	       (replace-match "" nil nil))
>> 	     (split-string (buffer-substring 1 (point-max)))
>> 	     )))
>>
>> For the toplevel, I am afraid one needs to restart it.  I guess a
>> similar trick is possible to automatically select the right one.
>>
>> Hope it helps,
>> C.