crystal2nix

README.md

Crystal2Nix

Since I don't have time to make a proper project for this, here's how to use it:

cd $YOU_RPROJECT
crystal crystal2nix.cr
ln -s $(nix-build crystal2nix.nix)/lib

crystal2nix.cr

require "json"
require "yaml"

yaml = YAML.parse(File.read("shard.lock"))
yaml["shards"].each do |key, value|
  next if value["revision"]?
  url = "https://github.com/#{value["github"]}"
  ref = "v#{value["version"]}"

  puts "git ls-remote #{ url } #{ ref }"
  Process.run("git", args: ["ls-remote", url, ref]) do |x|
    x.error.each_line do |e|
      puts e
    end

    x.output.each_line do |o|
      value.as_h["revision"] = o.split("\t")[0]
    end
  end
end

File.write "shard.lock", yaml.to_yaml

crystal2nix.nix

with import <nixpkgs> {};
with builtins;
let
  shard-json = stdenv.mkDerivation {
    name = "shard-json";
    src = ./shard.lock;
    buildInputs = [remarshal];
    phases = "buildPhase";
    buildPhase = ''
      remarshal --indent-json -if yaml -i $src -of json -o $out
    '';
  };
  projects = (fromJSON ( readFile "${ shard-json }" )).shards;
  projectSources = map (projectName:
    let project = projects.${projectName}; in
    stdenv.mkDerivation {
      name = replaceStrings ["/"] ["-"] projectName;
      src = fetchGit {
        url = if project?github then
                "https://github.com/" + project.github
              else
                abort ( "Don't know how to handle" + projectName );
        ref = "v${project.version}";
        rev = project.revision;
      };
      phases = "buildPhase";
      buildPhase = ''
        mkdir -p $out/package
        cp -r $src/* $out/package
        echo "${projectName}" > $out/name
      '';
    }
  ) (attrNames projects );
in stdenv.mkDerivation {
  name = "depTree";
  src = projectSources;
  phases = "buildPhase";
  buildPhase = ''
    mkdir -p $out
    for pkg in $src; do
      echo building $pkg
      name="$(cat $pkg/name)"
      mkdir -p $out/lib/$name
      cp -r $pkg/package/* $out/lib/$name
    done
  '';
}