Nix: installing ssreflect

Question

I am using Coq (versions 8.5-6), installed w/ Nix. I want to install ssreflect, preferably also w/ Nix. The only information I found about this is here . However, this is not about installing ssreflect, merely trying it out. Nevertheless, I tried to try it out, but ended up w/ hundreds of warnings (about the contents of various .v and .ml4 files) and couldn't wait for the process to end. A fairly typical warning looked like this:

File "./algebra/ssralg.v", line 856, characters 0-39: Warning: Implicit Arguments is deprecated; use Arguments instead

So the question: How on earth do I install ssreflect w/ Nix?

EDIT: After reading ejgallego's comments, it seems it may be impossible to install ssreflect w/ Nix -- esp. if one wants install only ssreflect w/out the other modules (fingroup, algebra, etc.). So I've also the following question:

Would the standard Opam or make install installation of ssreflect work w/ a Nix-installed Coq?

Answer 1

There are a few things that you need to be aware of:

• Nix is a source-based package manager with a binary cache. A lot of packages are pre-built and available in the binary cache, thus their installation doesn't take long; some packages (in particular development libraries) are not pre-built and Nix, when installing them will take the time it needs to compile them. Please be patient: you will only need to wait for the full compilation the first time (and yes, math-comp emits lots of warning upon compilation); next times, the package will be already available in your local Nix store.

• Since OPAM is also source-based, using OPAM instead of Nix won't make you save time. You can't mixup Nix-installed Coq with OPAM installed SSReflect because the latter will want the former as an OPAM dependency.

• The Nix way to use libraries is not to install them but to load them with nix-shell instead. nix-shell will "install" the libraries and set some environment variables for you (eg $COQPATH in this case).

• You can also compile the package from source yourself using a Nix-installed Coq but you cannot run make install because this would try to install SSReflect at the same place where Coq is installed but the Nix store is non-mutable. Instead you could skip this step, and set up $COQPATH manually.

• Indeed, the compilation of the full math-comp takes very long. There is a Coq ssreflect package which is lighter. You can get it using:

   nix-shell -p coqPackages_8_6.ssreflect