在 OPAM 中安装软件包列表

Question

OPAM is a great Package Manager for OCaml.

Is there a way to install a given list of packages like pip does in Python (with the command pip -r requirements.txt )?

We have a small Git repo shared with several people and it would be nice to just install all project dependencies in one go.

And yes, we might have a little shell script or list the packages in a.txt file and pipe it to opam install ... but there might be a better solution.

Thanks

Answer 1

Assuming you have your dependencies specified in NAME.opam (or just opam ) file in your project, you can run

opam install . --deps-only

This will install all dependencies for your package (or packages if you have several opam files in your project).

By default opam ignores uncommitted changes, so if you want to run this command with modified opam files you'll need to add --working-dir .

Optionally you could lock down versions of dependencies used by running opam lock , this will create .opam.locked files. opam-lock is a separate plugin in 2.0.5 (and likely until 2.1), so opam will prompt to install it.

With lock files present, you should also add --locked to opam install to ask it to use lock file and install exactly the same versions.

I would also recommend adding -j X where X is the number of cores you have available, that will speed things up.

I typically have the following in my Makefiles:

deps:
        opam install . --deps-only --locked --working-dir

The syntax of .opam files is described here