adding-packages.md

Adding Packages

Package Set: Git

Packages are added by adding a package description attributes set to either ps-pkgs.nix or ps-pkgs-ns.nix, or by adding your package to the official package set and updating the generated nix.
The packages descriptions sets consist of two parts:

{ src.git
, info
}

• src.git: An attrset that has repo and rev attributes, as well as an optional ref attribute if need be.
• info: info supports two variants. It is either a literal attrset containing the info, or an absolute path to a function that returns the info, relative to the source specified with src.

Example

# ...

arrays =
  { src.git =
      { repo = "https://github.com/purescript/purescript-arrays.git";
        rev = "d20bae2f76db6cf29b7b75e26e82b8a54c32295e";
      };

    info =
     { version = "7.0.0";

       dependencies =
         [ bifunctors
           control
           foldable-traversable
           maybe
           nonempty
           partial
           prelude
           st
           tailrec
           tuples
           unfoldable
           unsafe-coerce
         ];
     }
  };

is-even =
  { src.git =
      { repo = "https://github.com/purs-nix/test-packages.git";
        rev = "7e50388792dfa720e52b23219021f3c350e6bb30";
      };

    info = /is-even/package.nix;
  };

# ...

The attributes supported by info are:

• version (without the "v" prefix)
• dependencies (default: [])
• foreign (default: {})
• pursuit (default: {})
• src (default: "src")
• install (default: "ln -s $src/${src} $out")

All of these are optional.

Using info as a path

If you're using a file in for the package info, you need to make sure it's a function that accepts attribute sets of arbitrary size, either by using the ... syntax or by not destructuring at all. This is to make sure purs-nix can call it with new arguments in the future and your package will still be compatible.
Here's an example:

{ ps-pkgs, ... }:
  with ps-pkgs;
  { version = "6.0.0";

    dependencies =
      [ bifunctors
        control
        foldable-traversable
        maybe
        nonempty
        partial
        prelude
        st
        tailrec
        tuples
        unfoldable
        unsafe-coerce
      ];
  }

The arguments that are currently passed are:
build build-set ps-pkgs ps-pkgs-ns licenses

build

purs-nix exports a build function that can be used to add packages to your project from arbitrary sources. It takes an argument in mostly the same form as described above, but with a few differences.

• name: You must specify a name attribute for the package.
• src.path: This is another type of source you can specify for build (and technically the package set as well). src.path takes a path or derivation that points to the source of the package.

build-set

purs-nix exports a build-set function that can be used to add packages to your project from arbitrary sources. It is used to build the standard ps-pkgs package set and therefore takes an attrset in the same form shown above.

Package Set: Flake

If your package includes foreign dependencies, the easiest way to include it in the package set is to build the package with build, using src.path = ./.; and then expose that as a package on your flake. Then you can add it to the packages set by using src.flake.url. The info attribute is not used because the package is already built. If your package is not default, you can use src.flake.package and give it a string corresponding to the package name. We do it this way, instead of just using builtins.getFlake directly, so that this information can be collected for purs-nix package-info/nix run purs-nix#package-info.<package>.