nixpkgs/pkgs/applications/misc/rxvt-unicode/wrapper.nix

{ callPackage
, symlinkJoin
, makeWrapper
, lib
, rxvt-unicode-unwrapped
, rxvt-unicode-plugins
, perlPackages
, configure ? { availablePlugins, ... }:
  { plugins = builtins.attrValues availablePlugins;
    extraDeps = [ ];
    perlDeps = [ ];
  }
}:

let
  availablePlugins = rxvt-unicode-plugins;

  # Transform the string "self" to the plugin itself.
  # It's needed for plugins like bidi who depends on the perl
  # package they provide themself.
  mkPerlDeps = p:
    let deps = p.perlPackages or [ ];
    in map (x: if x == "self" then p else x) deps;

  # The wrapper is called with a `configure` function
  # that takes the urxvt plugins as input and produce
  # the configuration of the wrapper: list of plugins,
  # extra dependencies and perl dependencies.
  # This provides simple way to customize urxvt using
  # the `.override` mechanism.
  wrapper = { configure, ... }:
    let 
      config = configure { inherit availablePlugins; };
      plugins = config.plugins or (builtins.attrValues availablePlugins);
      extraDeps = config.extraDeps or [ ];
      perlDeps = (config.perlDeps or [ ]) ++ lib.concatMap mkPerlDeps plugins;
    in
      symlinkJoin {
        name = "rxvt-unicode-${rxvt-unicode-unwrapped.version}";

        paths = [ rxvt-unicode-unwrapped ] ++ plugins ++ extraDeps;

        buildInputs = [ makeWrapper ];

        postBuild = ''
          wrapProgram $out/bin/urxvt \
            --prefix PERL5LIB : "${perlPackages.makePerlPath perlDeps}" \
            --suffix-each URXVT_PERL_LIB ':' "$out/lib/urxvt/perl"
          wrapProgram $out/bin/urxvtd \
            --prefix PERL5LIB : "${perlPackages.makePerlPath perlDeps}" \
            --suffix-each URXVT_PERL_LIB ':' "$out/lib/urxvt/perl"
        '';

        passthru.plugins = plugins;
      };

in
  lib.makeOverridable wrapper { inherit configure; }