完成，一个小玩具

package.nix

@@ -0,0 +1,59 @@
+{
+  stdenv,
+  fetchurl,
+
+  # dependencies
+  mame,
+  which,
+  p7zip,
+  ...
+}:
+let
+  bin = ./lmxg-mu50;
+  desktop = ./lmxg-mu50.desktop;
+  icon = ./lmxg-mu50.png;
+in
+stdenv.mkDerivation rec {
+  pname = "lmxg-mu50";
+  version = "0.1.0";
+
+  src = fetchurl {
+    url = "https://mdk.cab/download/nonmerged/mu50";
+    sha256 = "sha256-0hzR2EWmamLJrqJ6cXaReEgd8Ha4Sf7LENpIYqcbCgs=";
+  };
+
+  nativeBuildInputs = [
+    p7zip
+  ];
+
+  buildInputs = [
+    mame
+    which
+  ];
+
+  phases = [
+    "unpackPhase"
+    "installPhase"
+  ];
+
+  unpackPhase = ''
+    mkdir -p mu50
+    cd mu50
+    7z x $src
+    cd ../
+  '';
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cat ${bin} | sed "s|@DIR@|$out|" > $out/bin/${pname}
+    chmod +x $out/bin/${pname}
+    mkdir -p $out/share/applications
+    cat ${desktop} | sed "s|@EXEC@|$out/bin/${pname}|" > $out/share/applications/${pname}.desktop
+    mkdir -p $out/share/pixmaps
+    cp ${icon} $out/share/pixmaps/${pname}.png
+
+    mkdir -p $out/share/mame/assets/mu50
+
+    cp -r /build/mu50 $out/share/mame/assets/
+  '';
+}