Loading topfind doesn't work

[murmour]

In the interactive toplevel (ocaml), loading topfind fails:

$ ocaml
        OCaml version 4.02.3

# #use "topfind";;
Cannot find file topfind.

The topfind file does exist:

$ test -f /home/mrm/.opam/system/lib/toplevel/topfind ; echo $?
0

And the environment variable is set correctly:

$ set | grep OCAML_TOPLEVEL_PATH
OCAML_TOPLEVEL_PATH=/home/mrm/.opam/system/lib/toplevel

If you put the file into current directory and name it topfind.ml, then #use "topfind" works.

And no, just renaming topfind into topfind.ml (without copying) doesn't work. It's probably that ocaml doesn't use the environment variable correctly, due to some path-related bug.

[dbuenzli]

I don't remember who's responsible for OCAML_TOPLEVEL_PATH and what it's supposed to do but it's it's not documented in the ocaml manual and a git grep on the ocaml repo returns nothing.

The issue here is that without additional -I given to ocaml a #use will only lookup in the cwd and ocamlc -where. So topfind should be installed in the latter directory, could you check the result of:

test -f $(ocamlc -where)/topfind ; echo $?

[murmour]

Indeed, that's the problem:

$ test -f $(ocamlc -where)/topfind ; echo $?
1

$ ocamlc -where
C:\OCaml\lib

I've tried copying topfind into C:\OCaml\lib\toplevel\, and it didn't help.
Possible solution: ocamlc -where should return /cygdrive/c/OCaml/lib.

[dbuenzli]

I've tried copying topfind into C:\OCaml\lib\toplevel\

You should copy it to C:\OCaml\lib.

[murmour]

I've tried copying topfind into C:\OCaml\lib\toplevel\

You should copy it to C:\OCaml\lib.

I did so, and it works! Thank you very much for assistance.
The installer should put it there as well -- it's how the issue is to be solved.

[protz]

Just for the record I'm eagerly waiting on David Allsopp's rumored, windows-compatible version of OPAM 2.0-beta. Once that is out, I'm hoping to decommission the installer.

[murmour]

Yeah, the rumors of @dra27's miracles are getting really strong lately. But for now, Jonathan, you are the champion of the forsaken souls on Windows. We worship you!

(starts drawing the pentagram)

[protz]

Hahah yes, indeed! Actually, https://github.com/fdopen/opam-repository-mingw works pretty well, and Andreas just recently released his patches