Extract Nix package and expose default overlay

docs/installation.md

@@ -33,6 +33,9 @@ nix profile install github:hooreique/fall
 
 ## Home Manager flake example
 
+The `overlays.default` overlay provides `pkgs.fall`, using dependencies from
+the package set it is applied to.
+
 Add `fall` to your flake:
 
 ```nix
@@ -49,7 +52,7 @@ Add `fall` to your flake:
     pkgs = import inputs.nixpkgs {
       inherit system;
       overlays = [
-        (final: prev: { fall = inputs.fall.packages.${system}.default; })
+        inputs.fall.overlays.default
       ];
     };
   in {

flake.nix

@@ -13,6 +13,15 @@
         );
     in
     {
+      overlays.default = final: prev: {
+        fall = final.callPackage ./package.nix { };
+      };
+
+      packages = forAllSys (pkgs: {
+        fall = pkgs.callPackage ./package.nix { };
+        default = pkgs.callPackage ./package.nix { };
+      });
+
       devShells = forAllSys (pkgs: {
         default = pkgs.mkShell {
           packages = [
@@ -22,45 +31,5 @@
           ];
         };
       });
-
-      packages = forAllSys (pkgs: {
-        default = pkgs.stdenvNoCC.mkDerivation {
-          pname = "fall";
-          version = "1.0.0";
-          src = ./.;
-
-          dontUnpack = true;
-          nativeBuildInputs = [ pkgs.makeWrapper ];
-
-          installPhase = ''
-            runHook preInstall
-
-            mkdir -p "$out/bin" "$out/share/fall"
-            cp "$src/fall.nu" "$src/codec.nu" "$out/share/fall/"
-
-            makeWrapper "${pkgs.nushell}/bin/nu" "$out/bin/fall" \
-              --prefix PATH : "${pkgs.lib.makeBinPath [ pkgs.gitMinimal ]}" \
-              --set FALL_GIT_SSH_COMMAND "${pkgs.openssh}/bin/ssh" \
-              --add-flags "$out/share/fall/fall.nu"
-
-            runHook postInstall
-          '';
-
-          meta = {
-            mainProgram = "fall";
-            description = "Shell helper to fetch and show status of many Git repositories";
-            longDescription = ''
-              **fall — Fetch ALL**
-
-              *fall* runs `git fetch` and `git status` over every repository path
-              listed in `~/.config/fall/repos.conf`, using parallel jobs for speed.
-              With `fall .`, it can instead work from a project-local `.repos.conf`
-              discovered by walking up the directory tree.
-            '';
-            homepage = "https://github.com/hooreique/fall";
-            license = pkgs.lib.licenses.mit;
-          };
-        };
-      });
     };
 }

package.nix

@@ -0,0 +1,46 @@
+{
+  lib,
+  stdenvNoCC,
+  makeWrapper,
+  nushell,
+  gitMinimal,
+  openssh,
+}:
+
+stdenvNoCC.mkDerivation {
+  pname = "fall";
+  version = "1.0.0";
+  src = ./.;
+
+  dontUnpack = true;
+  nativeBuildInputs = [ makeWrapper ];
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p "$out/bin" "$out/share/fall"
+    cp "$src/fall.nu" "$src/codec.nu" "$out/share/fall/"
+
+    makeWrapper "${nushell}/bin/nu" "$out/bin/fall" \
+      --prefix PATH : "${lib.makeBinPath [ gitMinimal ]}" \
+      --set FALL_GIT_SSH_COMMAND "${openssh}/bin/ssh" \
+      --add-flags "$out/share/fall/fall.nu"
+
+    runHook postInstall
+  '';
+
+  meta = {
+    mainProgram = "fall";
+    description = "Shell helper to fetch and show status of many Git repositories";
+    longDescription = ''
+      **fall — Fetch ALL**
+
+      *fall* runs `git fetch` and `git status` over every repository path
+      listed in `~/.config/fall/repos.conf`, using parallel jobs for speed.
+      With `fall .`, it can instead work from a project-local `.repos.conf`
+      discovered by walking up the directory tree.
+    '';
+    homepage = "https://github.com/hooreique/fall";
+    license = lib.licenses.mit;
+  };
+}