Can I use opam to make a package out of a local file and install it?

Question

I'm new to opam and trying to figure out how to use it properly. For a class, I want to set up students with an environment that has some custom packages installed. (The package will consist of some raw .ml files that I got from a colleague at another school; the files are on their github but there's no .opam file that I can see, and as far as I know they're not in any official package release.)

Can I somehow call these local .ml files a package and ask opam to install it? Do the files have to be on github first, and if so can I use my colleague's existing repository as the source? I don't want to make any of this public, since it is not my own work; I just want to configure my local environment so that the code in the files can be included easily as a package. Basically I don't know the best way to proceed so I'm happy for any advice.

Answer 1

You can add a custom opam file in the base directory of the project. See the documentation for how to create that file.

Then you can enter opam pin add . in the base directory and your project will be installed as if it was an opam package. Check opam pin --help for more info (you can also pin to a remote git project for instance).

Note that though the default repository is hosted on github, this is in no way a requirement for opam. Opam is dependent on git but you can absolutely use it with a private git repository. If you want to use your colleague's repository as the source, that is totally doable though it is often preferable to have the opam file at the root of the directory (you can do a PR on their repository or make your own fork of it on github, the site makes it clear you copied the code).

If pinning is not to your taste, you can also create your own repository though this is probably a bit too heavyweight for your needs.

Good luck!