nixpkgs/doc/languages-frameworks/idris.section.md

Idris packages

Installing Idris

The easiest way to get a working idris version is to install the idris attribute:

$ # On NixOS
$ nix-env -i nixos.idris
$ # On non-NixOS
$ nix-env -i nixpkgs.idris

This however only provides the prelude and base libraries. To install idris with additional libraries, you can use the idrisPackages.with-packages function, e.g. in an overlay in ~/.config/nixpkgs/overlays/my-idris.nix:

self: super: {
  myIdris = with self.idrisPackages; with-packages [ contrib pruviloj ];
}

And then:

$ # On NixOS
$ nix-env -iA nixos.myIdris
$ # On non-NixOS
$ nix-env -iA nixpkgs.myIdris

To see all available Idris packages:

$ # On NixOS
$ nix-env -qaPA nixos.idrisPackages
$ # On non-NixOS
$ nix-env -qaPA nixpkgs.idrisPackages

Similarly, entering a nix-shell:

$ nix-shell -p 'idrisPackages.with-packages (with idrisPackages; [ contrib pruviloj ])'

Starting Idris with library support

To have access to these libraries in idris, call it with an argument -p <library name> for each library:

$ nix-shell -p 'idrisPackages.with-packages (with idrisPackages; [ contrib pruviloj ])'
[nix-shell:~]$ idris -p contrib -p pruviloj

A listing of all available packages the Idris binary has access to is available via --listlibs:

$ idris --listlibs
00prelude-idx.ibc
pruviloj
base
contrib
prelude
00pruviloj-idx.ibc
00base-idx.ibc
00contrib-idx.ibc

Building an Idris project with Nix

As an example of how a Nix expression for an Idris package can be created, here is the one for idrisPackages.yaml:

{ build-idris-package
, fetchFromGitHub
, contrib
, lightyear
, lib
}:
build-idris-package  {
  name = "yaml";
  version = "2018-01-25";

  # This is the .ipkg file that should be built, defaults to the package name
  # In this case it should build `Yaml.ipkg` instead of `yaml.ipkg`
  # This is only necessary because the yaml packages ipkg file is
  # different from its package name here.
  ipkgName = "Yaml";
  # Idris dependencies to provide for the build
  idrisDeps = [ contrib lightyear ];

  src = fetchFromGitHub {
    owner = "Heather";
    repo = "Idris.Yaml";
    rev = "5afa51ffc839844862b8316faba3bafa15656db4";
    sha256 = "1g4pi0swmg214kndj85hj50ccmckni7piprsxfdzdfhg87s0avw7";
  };

  meta = {
    description = "Idris YAML lib";
    homepage = https://github.com/Heather/Idris.Yaml;
    license = lib.licenses.mit;
    maintainers = [ lib.maintainers.brainrape ];
  };
}

Assuming this file is saved as yaml.nix, it's buildable using

$ nix-build -E '(import <nixpkgs> {}).idrisPackages.callPackage ./yaml.nix {}'

Or it's possible to use

with import <nixpkgs> {};

{
  yaml = idrisPackages.callPackage ./yaml.nix {};
}

in another file (say default.nix) to be able to build it with

$ nix-build -A yaml