build: separated the nix flake and derivation, to allow for simpler builds and more flexibility

default.nix

@@ -0,0 +1,9 @@
+{ pkgs ? import <nixpkgs> {}, ...}:
+
+pkgs.ocamlPackages.buildDunePackage {
+  pname = "ollisp";
+  version = "0.0.1";
+  src = pkgs.lib.cleanSource ./.;
+  nativeBuildInputs = with pkgs.ocamlPackages; [findlib menhir dune_3 ocaml];
+  buildInputs = with pkgs.ocamlPackages; [];
+}

flake.nix

@@ -9,23 +9,8 @@
     flake-utils.lib.eachDefaultSystem (system:
   let
     pkgs = nixpkgs.legacyPackages.${system};
-    devInputs = with pkgs.ocamlPackages; [merlin];
-    ocamlPkgs = with pkgs.ocamlPackages; [menhir dune_3];
-    libs = with pkgs.ocamlPackages; [findlib];
-    nativeInputs =  with pkgs; ocamlPkgs ++ [ocaml];
   in
   {
-    packages.default = (pkgs.ocamlPackages.buildDunePackage {
+    packages.default = pkgs.callPackage ./default.nix {};
-      pname = "ollisp";
-      version = "0.0.1";
-      src = pkgs.lib.cleanSource ./.;
-      nativeBuildInputs = nativeInputs;
-      buildInputs = libs;
-    });
-    
-    devShells.default = pkgs.mkShell {
-      nativeBuildInputs = nativeInputs ++ devInputs;
-      buildInputs = libs;
-    };
   });
 }