Reimplement framework using the module system

builtin-modules/default-formatters.nix

@@ -1,7 +0,0 @@
-_: {
-  devTools = pkgs: with pkgs; [ nixpkgs-fmt nodePackages.prettier ];
-  formatters = {
-    "*.nix" = "nixpkgs-fmt";
-    "*.md | *.json | *.yml" = "prettier --write";
-  };
-}

builtin-modules/editorconfig.nix

@@ -1,13 +0,0 @@
-{ src, lib }:
-let
-  inherit (lib) getExe optionalAttrs optionalString pathExists;
-in
-{
-  checks = optionalAttrs (pathExists (src + /.editorconfig)) {
-    # By default, high false-positive flags are disabled.
-    editorconfig = { editorconfig-checker }:
-      "${getExe editorconfig-checker}"
-      + optionalString (!pathExists (src + /.ecrc))
-        " -disable-indent-size -disable-max-line-length";
-  };
-}

builtin-modules/pre-commit-hook.nix

@@ -1,10 +0,0 @@
-_: {
-  shellHook = { lib, flakelite }: ''
-    if [ -f flake.nix ] && [ -d .git/hooks ] &&
-       [ ! -f .git/hooks/pre-commit ]; then
-      echo Installing git pre-commit hook...
-      cp ${lib.getExe flakelite.inputs'.flakelite.packages.pre-commit-hook
-          } .git/hooks
-    fi
-  '';
-}

builtinModules/apps.nix

@@ -0,0 +1,43 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, lib, flakelite, ... }:
+let
+  inherit (lib) isFunction mapAttrs mkIf mkMerge mkOption;
+  inherit (lib.types) lazyAttrsOf nullOr raw;
+  inherit (flakelite.types) optFunctionTo;
+
+  isApp = x: (x ? type) && (x.type == "app") && (x ? program);
+
+  mkApp = pkgs: app:
+    let
+      app' = if isFunction app then app pkgs else app;
+    in
+    if isApp app' then app' else { type = "app"; program = "${app'}"; };
+in
+{
+  options = {
+    app = mkOption {
+      type = nullOr raw;
+      default = null;
+    };
+
+    apps = mkOption {
+      type = nullOr (optFunctionTo (lazyAttrsOf raw));
+      default = null;
+    };
+  };
+
+  config = mkMerge [
+    (mkIf (config.app != null) {
+      apps.default = config.app;
+    })
+
+    (mkIf (config.apps != null) {
+      perSystem = pkgs: {
+        apps = mapAttrs (_: mkApp pkgs) (config.apps pkgs);
+      };
+    })
+  ];
+}

builtinModules/builtinFormatters.nix

@@ -0,0 +1,24 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ lib, ... }:
+let
+  inherit (lib) mkEnableOption;
+in
+{
+  options.flakelite.builtinFormatters =
+    mkEnableOption "default formatters" // { default = true; };
+
+  config = {
+    devShell.packages = pkgs: [
+      pkgs.nixpkgs-fmt
+      pkgs.nodePackages.prettier
+    ];
+
+    formatters = {
+      "*.nix" = "nixpkgs-fmt";
+      "*.md | *.json | *.yml" = "prettier --write";
+    };
+  };
+}

builtinModules/builtinOverlay.nix

@@ -0,0 +1,46 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, src, lib, inputs, outputs, flakelite, ... }:
+let
+  inherit (lib) isList mkOption mkOrder mapAttrs optionalAttrs;
+  inherit (lib.types) listOf nullOr oneOf str;
+in
+{
+  options = {
+    description = mkOption {
+      type = nullOr str;
+      default = null;
+    };
+
+    license = mkOption {
+      type = nullOr (oneOf [ str (listOf str) ]);
+      default = null;
+    };
+  };
+
+  config.withOverlays = mkOrder 10 (final: prev:
+    let
+      system = prev.stdenv.hostPlatform.system;
+    in
+    {
+      inherit src inputs outputs flakelite system;
+      inputs' = mapAttrs (_: mapAttrs (_: v: v.${system} or { })) inputs;
+      outputs' = mapAttrs (_: v: v.${system} or { }) outputs;
+
+      defaultMeta = {
+        platforms = config.systems;
+      } // optionalAttrs (config.description != null) {
+        inherit (config) description;
+      } // optionalAttrs (config.license != null) {
+        license =
+          let
+            getLicense = license: final.lib.licenses.${license} or
+              (final.lib.meta.getLicenseFromSpdxId license);
+          in
+          if isList config.license then map getLicense config.license
+          else getLicense config.license;
+      };
+    });
+}

builtinModules/checks.nix

@@ -0,0 +1,32 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, src, lib, flakelite, ... }:
+let
+  inherit (lib) isDerivation isFunction mkOption mkIf mapAttrs;
+  inherit (lib.types) lazyAttrsOf nullOr raw;
+  inherit (flakelite.types) optFunctionTo;
+
+  mkCheck = pkgs: src: name: cmd:
+    let
+      cmd' = if isFunction cmd then cmd pkgs else cmd;
+    in
+    if isDerivation cmd' then cmd' else
+    pkgs.runCommand "check-${name}" { } ''
+      cp --no-preserve=mode -r ${src} src
+      cd src
+      ${cmd'}
+      touch $out
+    '';
+in
+{
+  options.checks = mkOption {
+    type = nullOr (optFunctionTo (lazyAttrsOf raw));
+    default = null;
+  };
+
+  config.perSystem = mkIf (config.checks != null) (pkgs: {
+    checks = mapAttrs (mkCheck pkgs src) (config.checks pkgs);
+  });
+}

builtinModules/core.nix

@@ -0,0 +1,69 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, inputs, lib, flakelite, ... }:
+let
+  inherit (builtins) all head isAttrs length;
+  inherit (lib) foldAttrs getFiles getValues mapAttrs mergeAttrs mkOption
+    mkOptionType showFiles showOption;
+  inherit (lib.types) functionTo lazyAttrsOf listOf nonEmptyStr raw uniq;
+  inherit (flakelite.types) optListOf overlay;
+
+  outputs = mkOptionType {
+    name = "outputs";
+    description = "output values";
+    descriptionClass = "noun";
+    merge = loc: defs:
+      if (length defs) == 1 then (head defs).value
+      else if all isAttrs (getValues defs) then
+        (lazyAttrsOf outputs).merge loc defs
+      else throw "The option `${showOption loc}' has conflicting definitions in ${showFiles (getFiles defs)}";
+  };
+in
+{
+  options = {
+    inputs = mkOption {
+      type = lazyAttrsOf raw;
+    };
+
+    systems = mkOption {
+      type = uniq (listOf nonEmptyStr);
+      default = [ "x86_64-linux" "aarch64-linux" ];
+    };
+
+    outputs = mkOption {
+      type = lazyAttrsOf outputs;
+      default = { };
+    };
+
+    perSystem = mkOption {
+      type = functionTo (lazyAttrsOf outputs);
+      default = _: { };
+    };
+
+    nixpkgs.config = mkOption {
+      type = lazyAttrsOf raw;
+      default = { };
+    };
+
+    withOverlays = mkOption {
+      type = optListOf overlay;
+      default = [ ];
+    };
+  };
+
+  config = {
+    _module.args = { inherit (config) inputs outputs; };
+
+    outputs = foldAttrs mergeAttrs { } (map
+      (system: mapAttrs
+        (_: v: { ${system} = v; })
+        (config.perSystem (import inputs.nixpkgs {
+          inherit system;
+          config = config.nixpkgs.config;
+          overlays = config.withOverlays;
+        })))
+      config.systems);
+  };
+}

builtinModules/devShells.nix

@@ -0,0 +1,70 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, lib, flakelite, ... }:
+let
+  inherit (lib) any attrValues filterAttrs mapAttrs mkIf mkMerge mkOption
+    optionalAttrs;
+  inherit (lib.types) lazyAttrsOf functionTo lines listOf nullOr package str;
+  inherit (flakelite) supportedSystem;
+  inherit (flakelite.types) optFunctionTo packageDef;
+in
+{
+  options = {
+    devShell = {
+      inputsFrom = mkOption {
+        type = nullOr
+          (functionTo (listOf package));
+        default = null;
+      };
+
+      packages = mkOption {
+        type = nullOr
+          (functionTo (listOf package));
+        default = null;
+      };
+
+      shellHook = mkOption {
+        type = nullOr (optFunctionTo lines);
+        default = null;
+      };
+
+      env = mkOption {
+        type = nullOr
+          (optFunctionTo (lazyAttrsOf str));
+        default = null;
+      };
+    };
+
+    devShells = mkOption {
+      type = lazyAttrsOf packageDef;
+      default = { };
+    };
+  };
+
+  config = mkMerge [
+    (mkIf (any (x: x != null) (attrValues config.devShell)) {
+      devShells.default = { pkgs, mkShell }: mkShell (
+        optionalAttrs (config.devShell.env != null)
+          (config.devShell.env pkgs)
+        // optionalAttrs (config.devShell.inputsFrom != null) {
+          inputsFrom = config.devShell.inputsFrom pkgs;
+        }
+        // optionalAttrs (config.devShell.packages != null) {
+          packages = config.devShell.packages pkgs;
+        }
+        // optionalAttrs (config.devShell.shellHook != null) {
+          shellHook = config.devShell.shellHook pkgs;
+        }
+      );
+    })
+
+    (mkIf (config.devShells != { }) {
+      perSystem = pkgs: {
+        devShells = filterAttrs (_: supportedSystem pkgs)
+          (mapAttrs (_: v: pkgs.callPackage v { }) config.devShells);
+      };
+    })
+  ];
+}

builtinModules/editorconfig.nix

@@ -0,0 +1,22 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, lib, src, ... }:
+let
+  inherit (lib) mkEnableOption mkIf optionalString pathExists;
+in
+{
+  options.flakelite.editorconfig =
+    mkEnableOption "editorconfig check" // { default = true; };
+
+  config.checks = mkIf
+    (config.flakelite.editorconfig && (pathExists (src + /.editorconfig)))
+    {
+      # By default, high false-positive flags are disabled.
+      editorconfig = { editorconfig-checker, ... }:
+        "${editorconfig-checker}/bin/editorconfig-checker"
+        + optionalString (!pathExists (src + /.ecrc))
+          " -disable-indent-size -disable-max-line-length";
+    };
+}

builtinModules/formatter.nix

@@ -0,0 +1,40 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, src, lib, flakelite, ... }:
+let
+  inherit (lib) mkOption mkIf mapAttrsToList;
+  inherit (lib.types) lazyAttrsOf nullOr str;
+  inherit (flakelite.types) optFunctionTo;
+in
+{
+  options.formatters = mkOption {
+    type = nullOr (optFunctionTo (lazyAttrsOf str));
+    default = null;
+  };
+
+  config = mkIf (config.formatters != null) {
+    perSystem = { pkgs, lib, fd, coreutils, ... }: {
+      formatter = pkgs.writeShellScriptBin "formatter" ''
+        PATH=${lib.makeBinPath (config.devShell.packages pkgs)}
+        for f in "$@"; do
+          if [ -d "$f" ]; then
+            ${fd}/bin/fd "$f" -Htf -x "$0"
+          else
+            case "$(${coreutils}/bin/basename "$f")" in
+              ${toString (mapAttrsToList
+                (n: v: "${n}) ${v} \"$f\";;") (config.formatters pkgs))}
+            esac
+          fi
+        done &>/dev/null
+      '';
+    };
+
+    checks.formatting = { lib, outputs', diffutils, ... }: ''
+      ${lib.getExe outputs'.formatter} .
+      ${diffutils}/bin/diff -qr ${src} . |\
+        sed 's/Files .* and \(.*\) differ/File \1 not formatted/g'
+    '';
+  };
+}

builtinModules/homeConfigurations.nix

@@ -0,0 +1,34 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, lib, ... }:
+let
+  inherit (builtins) isAttrs;
+  inherit (lib) foldl mapAttrsToList mergeOneOption mkOption mkOptionType mkIf
+    recursiveUpdate;
+  inherit (lib.types) lazyAttrsOf;
+
+  homeConfiguration = mkOptionType {
+    name = "homeConfiguration";
+    description = "homeConfiguration";
+    descriptionClass = "noun";
+    check = x: isAttrs x && x ? activationPackage;
+    merge = mergeOneOption;
+  };
+in
+{
+  options.homeConfigurations = mkOption {
+    type = lazyAttrsOf homeConfiguration;
+    default = { };
+  };
+
+  config.outputs = mkIf (config.homeConfigurations != { }) {
+    inherit (config) homeConfigurations;
+    checks = foldl recursiveUpdate { } (mapAttrsToList
+      (n: v: {
+        ${v.config.nixpkgs.system}."home-${n}" = v.activationPackage;
+      })
+      config.homeConfigurations);
+  };
+}

builtinModules/homeModules.nix

@@ -0,0 +1,33 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, lib, flakelite, ... }:
+let
+  inherit (lib) mkOption mkIf mkMerge;
+  inherit (lib.types) lazyAttrsOf nullOr;
+  inherit (flakelite.types) module;
+in
+{
+  options = {
+    homeModule = mkOption {
+      type = nullOr module;
+      default = null;
+    };
+
+    homeModules = mkOption {
+      type = lazyAttrsOf module;
+      default = { };
+    };
+  };
+
+  config = mkMerge [
+    (mkIf (config.homeModule != null) {
+      homeModules.default = config.homeModule;
+    })
+
+    (mkIf (config.homeModules != { }) {
+      outputs = { inherit (config) homeModules; };
+    })
+  ];
+}

builtinModules/nixDir.nix

@@ -0,0 +1,75 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, src, lib, flakelite, ... }@args:
+let
+  inherit (lib) isFunction mkOption mkIf mkMerge optionalAttrs;
+  inherit (flakelite) autoImport;
+  inherit (flakelite.types) path;
+in
+{
+  options.nixDir = mkOption {
+    type = path;
+    default = src + /nix;
+  };
+
+  config =
+    let
+      autoImport' = autoImport config.nixDir;
+      autoImportArgs = n:
+        let v = autoImport' n; in
+        if isFunction v then v args else v;
+      outputs = autoImportArgs "outputs";
+      perSystem = autoImport' "perSystem";
+      withOverlays = autoImport' "withOverlays";
+      package = autoImport' "package";
+      packages = autoImportArgs "packages";
+      overlays = autoImportArgs "overlays";
+      devShell = autoImportArgs "devShell";
+      devShells = autoImportArgs "devShells";
+      app = autoImport' "app";
+      apps = autoImport' "apps";
+      checks = autoImport' "checks";
+      nixosModule = autoImport' "nixosModule";
+      nixosModules = autoImportArgs "nixosModules";
+      nixosConfigurations = autoImportArgs [ "nixosConfigurations" "nixos" ];
+      homeModule = autoImport' "homeModule";
+      homeModules = autoImportArgs "homeModules";
+      homeConfigurations = autoImportArgs [ "homeConfigurations" "home" ];
+      template = autoImportArgs "template";
+      templates = autoImportArgs "templates";
+      formatters = autoImport' "formatters";
+    in
+    mkMerge [
+      (mkIf (outputs != null) { inherit outputs; })
+      (mkIf (perSystem != null) { inherit perSystem; })
+      (mkIf (withOverlays != null) { inherit withOverlays; })
+      (mkIf (package != null) { inherit package; })
+      (mkIf (packages != null) { inherit packages; })
+      (mkIf (overlays != null) { inherit overlays; })
+      (mkIf (devShell != null) {
+        devShell = optionalAttrs (devShell ? inputsFrom)
+          { inherit (devShell) inputsFrom; }
+        // optionalAttrs (devShell ? packages)
+          { inherit (devShell) packages; }
+        // optionalAttrs (devShell ? shellHook)
+          { inherit (devShell) shellHook; }
+        // optionalAttrs (devShell ? env)
+          { inherit (devShell) env; };
+      })
+      (mkIf (devShells != null) { inherit devShells; })
+      (mkIf (app != null) { inherit app; })
+      (mkIf (apps != null) { inherit apps; })
+      (mkIf (checks != null) { inherit checks; })
+      (mkIf (nixosModule != null) { inherit nixosModule; })
+      (mkIf (nixosModules != null) { inherit nixosModules; })
+      (mkIf (nixosConfigurations != null) { inherit nixosConfigurations; })
+      (mkIf (homeModule != null) { inherit homeModule; })
+      (mkIf (homeModules != null) { inherit homeModules; })
+      (mkIf (homeConfigurations != null) { inherit homeConfigurations; })
+      (mkIf (template != null) { inherit template; })
+      (mkIf (templates != null) { inherit templates; })
+      (mkIf (formatters != null) { inherit formatters; })
+    ];
+}

builtinModules/nixosConfigurations.nix

@@ -0,0 +1,37 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, lib, ... }:
+let
+  inherit (builtins) isAttrs;
+  inherit (lib) foldl mapAttrsToList mergeOneOption mkIf mkOption mkOptionType
+    recursiveUpdate;
+  inherit (lib.types) lazyAttrsOf;
+
+  nixosConfiguration = mkOptionType {
+    name = "nixosConfiguration";
+    description = "nixosConfiguration";
+    descriptionClass = "noun";
+    check = x: isAttrs x
+      && x ? config.nixpkgs.system
+      && x ? config.system.build.toplevel;
+    merge = mergeOneOption;
+  };
+in
+{
+  options.nixosConfigurations = mkOption {
+    type = lazyAttrsOf nixosConfiguration;
+    default = { };
+  };
+
+  config.outputs = mkIf (config.nixosConfigurations != { }) {
+    inherit (config) nixosConfigurations;
+    checks = foldl recursiveUpdate { } (mapAttrsToList
+      (n: v: {
+        ${v.config.nixpkgs.system}."nixos-${n}" =
+          v.config.system.build.toplevel;
+      })
+      config.nixosConfigurations);
+  };
+}

builtinModules/nixosModules.nix

@@ -0,0 +1,33 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, lib, flakelite, ... }:
+let
+  inherit (lib) mkOption mkIf mkMerge;
+  inherit (lib.types) lazyAttrsOf nullOr;
+  inherit (flakelite.types) module;
+in
+{
+  options = {
+    nixosModule = mkOption {
+      type = nullOr module;
+      default = null;
+    };
+
+    nixosModules = mkOption {
+      type = lazyAttrsOf module;
+      default = { };
+    };
+  };
+
+  config = mkMerge [
+    (mkIf (config.nixosModule != null) {
+      nixosModules.default = config.nixosModule;
+    })
+
+    (mkIf (config.nixosModules != { }) {
+      outputs = { inherit (config) nixosModules; };
+    })
+  ];
+}

builtinModules/overlays.nix

@@ -0,0 +1,18 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, lib, flakelite, ... }:
+let
+  inherit (lib) mkOption mkIf;
+  inherit (lib.types) lazyAttrsOf;
+  inherit (flakelite.types) overlay;
+in
+{
+  options.overlays = mkOption {
+    type = lazyAttrsOf overlay;
+    default = { };
+  };
+
+  config.outputs = mkIf (config.overlays != { }) { inherit (config) overlays; };
+}

builtinModules/packages.nix

@@ -0,0 +1,68 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, lib, flakelite, ... }:
+let
+  inherit (builtins) attrNames functionArgs intersectAttrs parseDrvName;
+  inherit (lib) composeManyExtensions filterAttrs fix genAttrs mapAttrs mapAttrs'
+    mkIf mkMerge mkOption mkOrder nameValuePair optional optionalAttrs remove;
+  inherit (lib.types) lazyAttrsOf nullOr;
+  inherit (flakelite) supportedSystem;
+  inherit (flakelite.types) packageDef;
+
+  getName = pkg: pkg.pname or (parseDrvName pkg.name).name;
+
+  callPkg = pkgs: def: def (intersectAttrs (functionArgs def) pkgs);
+in
+{
+  options = {
+    package = mkOption {
+      type = nullOr packageDef;
+      default = null;
+    };
+
+    packages = mkOption {
+      type = lazyAttrsOf packageDef;
+      default = { };
+    };
+  };
+
+  config = mkMerge [
+    (mkIf (config.package != null) {
+      packages.default = config.package;
+    })
+
+    (mkIf (config.packages != { }) {
+      withOverlays = mkOrder 2000 (final: prev:
+        let
+          pkgNames = attrNames config.packages;
+          pkgNames' = remove "default" pkgNames;
+          defaultName = getName (fix (self:
+            prev // (genAttrs pkgNames
+              (n: callPkg self config.packages.${n})))).default;
+        in
+        (optionalAttrs (config.packages ? default) {
+          ${defaultName} = final.callPackage config.packages.default { };
+        }) //
+        (genAttrs pkgNames' (n: final.callPackage config.packages.${n} { })));
+
+      overlays.default = final: prev:
+        let
+          pkgs' = fix (composeManyExtensions config.withOverlays) prev;
+          defaultName = getName (callPkg pkgs' config.packages.default);
+          pkgNames = (remove "default" (attrNames config.packages))
+            ++ (optional (config.packages ? default) defaultName);
+          pkgs = final.appendOverlays config.withOverlays;
+        in
+        genAttrs pkgNames (n: pkgs.${n});
+
+      perSystem = pkgs: rec {
+        packages = filterAttrs (_: supportedSystem pkgs)
+          (mapAttrs (_: v: pkgs.callPackage v { }) config.packages);
+
+        checks = mapAttrs' (n: nameValuePair ("packages-" + n)) packages;
+      };
+    })
+  ];
+}

builtinModules/templates.nix

@@ -0,0 +1,42 @@
+# flakelite -- Framework for making flakes simple
+# Copyright (C) 2023 Archit Gupta <archit@accelbread.com>
+# SPDX-License-Identifier: MIT
+
+{ config, lib, ... }:
+let
+  inherit (builtins) isPath isString;
+  inherit (lib) mkOption mkOptionType mkIf mkMerge;
+  inherit (lib.types) lazyAttrsOf nullOr;
+
+  template = mkOptionType {
+    name = "template";
+    description = "template definition";
+    descriptionClass = "noun";
+    check = x: (x ? path) && (isPath x.path) &&
+      (x ? description) && (isString x.description) &&
+      ((! x ? welcomeText) || (isString x.welcomeText));
+  };
+in
+{
+  options = {
+    template = mkOption {
+      type = nullOr template;
+      default = null;
+    };
+
+    templates = mkOption {
+      type = lazyAttrsOf template;
+      default = { };
+    };
+  };
+
+  config = mkMerge [
+    (mkIf (config.template != null) {
+      templates.default = config.template;
+    })
+
+    (mkIf (config.templates != { }) {
+      outputs = { inherit (config) templates; };
+    })
+  ];
+}

default.nix

@@ -4,65 +4,69 @@
 
 localInputs:
 let
-  inherit (builtins) intersectAttrs isPath readDir;
-  inherit (localInputs.nixpkgs.lib) attrNames attrVals attrValues
-    callPackageWith composeManyExtensions concat concatStringsSep filter
-    filterAttrs findFirst foldAttrs foldl functionArgs genAttrs hasSuffix
-    isFunction isList isString listToAttrs mapAttrs mapAttrsToList mapAttrs'
-    mergeAttrs nameValuePair optional optionalAttrs parseDrvName pathExists pipe
-    recursiveUpdate removePrefix removeSuffix zipAttrsWith;
+  inherit (builtins) isAttrs isPath readDir;
+  inherit (localInputs.nixpkgs.lib) attrNames composeManyExtensions
+    filter findFirst genAttrs getValues hasSuffix isFunction isList mapAttrs
+    mapAttrsToList pathExists pipe removePrefix removeSuffix evalModules
+    mkDefault mkOptionType singleton;
+  inherit (localInputs.nixpkgs.lib.types) coercedTo functionTo listOf;
 
-  /* Attributes in flakelite's lib output.
-  */
-  exports = {
-    inherit mkFlake systems importDir autoImport autoImportAttrs defaultPkgName
-      supportedSystem mergeModules moduleAttrs rootAttrs ensureFn callFn
-      filterArgs callPkg callPkgs tryImport mkApp mkCheck liftFn2 fnConcat
-      fnMergeAttrs;
-  };
+  builtinModules = mapAttrsToList (k: _: ./builtinModules + ("/" + k))
+    (readDir ./builtinModules);
 
-  /* Module which is always included as first module.
-  */
-  baseModule = { inputs, root, args }: {
-    # Ensures nixpkgs and flakelite are available for modules.
-    inputs = {
-      flakelite = localInputs.self;
-      inherit (localInputs) nixpkgs;
-    };
-    withOverlay = final: prev: {
-      # Allows access to flakelite lib functions from package sets.
-      # Also adds pkgs-specific additional args.
-      flakelite = args // {
-        # Inputs with system auto-selected.
-        # i.e. inputs.self.packages.${system} -> inputs'.self.packages
-        inputs' = mapAttrs
-          (_: mapAttrs
-            (_: v: v.${prev.system} or { }))
-          inputs;
-        # Default package meta attribute generated from root module attrs.
-        meta = {
-          platforms = root.systems;
-        } // optionalAttrs (root ? description) {
-          inherit (root) description;
-        } // optionalAttrs (root ? license) {
-          license =
-            if isList root.license
-            then attrVals root.license final.lib.licenses
-            else final.lib.licenses.${root.license};
-        };
+  mkFlake = src: root: (evalModules {
+    specialArgs.modulesPath = ./builtinModules;
+    modules = builtinModules ++ [
+      { inputs.nixpkgs = mkDefault localInputs.nixpkgs; }
+      { _module.args = { inherit src flakelite; }; }
+      root
+    ];
+  }).config.outputs;
+
+  flakelite = {
+    inherit mkFlake supportedSystem importDir autoImport;
+
+    types = {
+      overlay = mkOptionType {
+        name = "overlay";
+        description = "nixpkgs overlay";
+        descriptionClass = "noun";
+        check = isFunction;
+        merge = _: defs: composeManyExtensions (getValues defs);
       };
-      # These attrs are important enough for top-level pkg set.
-      inherit (final.flakelite) inputs inputs';
+
+      packageDef = mkOptionType {
+        name = "packageDef";
+        description = "package definition";
+        descriptionClass = "noun";
+        check = isFunction;
+      };
+
+      path = mkOptionType {
+        name = "path";
+        description = "path";
+        descriptionClass = "noun";
+        check = isPath;
+      };
+
+      module = mkOptionType {
+        name = "module";
+        description = "module";
+        descriptionClass = "noun";
+        check = x: isPath x || isFunction x || isAttrs x;
+        merge = _: defs: { imports = getValues defs; };
+      };
+
+      optListOf = elemType: coercedTo elemType singleton (listOf elemType);
+
+      optFunctionTo = elemType: coercedTo elemType (x: _: x)
+        (functionTo elemType);
     };
   };
 
-  builtinModules = attrValues (importDir ./builtin-modules);
+  supportedSystem = { lib, stdenv, ... }:
+    lib.meta.availableOn stdenv.hostPlatform;
 
-  /* Import each nix file in a directory as attrs. Attr name is file name with
-     extension stripped. To allow use in an importable directory, default.nix is
-     skipped. To provide a file that will result in a "default" attr, name the
-     file "_default.nix".
-  */
   importDir = path: genAttrs
     (pipe (readDir path) [
       attrNames
@@ -74,12 +78,6 @@ let
     (p: import (path + (if pathExists
       (path + "/_${p}.nix") then "/_${p}.nix" else "/${p}.nix")));
 
-  /* Try to load a name from a directory. If a nix file by that name exits,
-     import it. If an importable directory with that name exists, import it.
-     Else, if a non-importable directory with that name exists, load the nix
-     files in that dir as an attrset. Returns null if the name could not be
-     loaded. If name is a list, tries all names in that list.
-  */
   autoImport = dir: name:
     if isList name
     then findFirst (x: x != null) null (map (autoImport dir) name)
@@ -92,428 +90,8 @@ let
       then importDir (dir + "/${name}")
       else null;
 
-  /* List of attrs that can be provided by a module.
-  */
-  moduleAttrs = [
-    "inputs"
-    "withOverlay"
-    "withOverlays"
-    "nixpkgsConfig"
-    "package"
-    "packages"
-    "devTools"
-    "shellHook"
-    "devShell"
-    "devShells"
-    "env"
-    "overlay"
-    "overlays"
-    "app"
-    "apps"
-    "checks"
-    "nixosModule"
-    "nixosModules"
-    "nixosConfigurations"
-    "homeModule"
-    "homeModules"
-    "homeConfigurations"
-    "template"
-    "templates"
-    "formatters"
-  ];
-
-  /* List of handled attrs in root module. Does not have optionally checked
-     attrs like name, description, or license, or attrs used by modules.
-  */
-  rootAttrs = moduleAttrs ++ [
-    "systems"
-    "perSystem"
-    "outputs"
-    "nixDir"
-  ];
-
-  /* Alternative names for autoloading root attrs.
-  */
-  attrAliases = {
-    "nixosConfigurations" = [ "nixos" ];
-    "homeConfigurations" = [ "home" ];
-    # Lets `nix-shell` shell.nix be used automatically if no ./nix dir.
-    "devShell" = [ "shell" ];
-    "nixpkgsConfig" = [ "nixpkgs/config" ];
-  };
-
-  /* Generate an attrset by importing attrs from dir. Filters null values.
-     Alternative names from aliases are used.
-  */
-  autoImportAttrs = dir: attrs: aliases:
-    filterAttrs (_: v: v != null) (genAttrs attrs
-      (attr: autoImport dir ([ attr ] ++ aliases.${attr} or [ ])));
-
-  /* Makes the parameter callable, if it isn't. This allows values that are not
-     always functions to be applied to parameters.
-  */
-  ensureFn = v: if isFunction v then v else _: v;
-
-  /* Takes a binary function and returns a binary function that operates on
-     functions that return the original parameter types.
-
-     Type: liftFn2 :: (a -> b -> c) -> (d -> a) -> (d -> b) -> d -> c
-  */
-  liftFn2 = fn: a: b: args: fn (a args) (b args);
-
-  fnConcat = liftFn2 concat;
-  fnMergeAttrs = liftFn2 mergeAttrs;
-
-  /* Takes a function which takes a list, and returns a binary function.
-
-     Type: mkBinary :: ([a] -> b) -> a -> a -> b
-  */
-  mkBinary = fn: a: b: fn [ a b ];
-
-  /* Merges attrsets of overlays, combining overlays with same name.
-  */
-  mergeOverlayAttrs = mkBinary (zipAttrsWith (_: composeManyExtensions));
-
-  fnConcatScripts = liftFn2 (mkBinary (concatStringsSep "\n"));
-
-  mergeModules = a: b: mapAttrs (n: v: v a.${n} b.${n}) {
-    inputs = mergeAttrs;
-    withOverlays = concat;
-    nixpkgsConfig = mergeAttrs;
-    packages = mergeAttrs;
-    devTools = fnConcat;
-    shellHook = fnConcatScripts;
-    devShells = fnMergeAttrs;
-    env = fnMergeAttrs;
-    overlays = mergeOverlayAttrs;
-    apps = fnMergeAttrs;
-    checks = fnMergeAttrs;
-    nixosModules = mergeAttrs;
-    nixosConfigurations = mergeAttrs;
-    homeModules = mergeAttrs;
-    homeConfigurations = mergeAttrs;
-    templates = mergeAttrs;
-    formatters = fnMergeAttrs;
-  };
-
-  /* Calls f with required arguments from args. If the function does not have
-     named arguments, just passes it args instead of nothing like callPackage
-     does. If f is not a function, returns f.
-  */
-  callFn = args: f:
-    let
-      f' = ensureFn f;
-    in
-    if functionArgs f' == { } then f' args
-    else f' (intersectAttrs (functionArgs f) args);
-
-  /* Ensures x is called with only it's required parameters.
-  */
-  filterArgs = x: args: callFn args x;
-
-  /* If arg is importable, imports it, else returns arg as is.
-  */
-  tryImport = x: if (isPath x) || (isString x) then import x else x;
-
-  /* Like callFn, but intended for functions that return derivations. Uses
-     callPackage so will make result overridable. Trys importing the value if a
-     path.
-  */
-  callPkg = args: f:
-    let
-      f' = ensureFn (tryImport f);
-    in
-    if functionArgs f' == { } then f' args
-    else (args.callPackage or (callPackageWith args)) f' { };
-
-  callPkgs = pkgs: mapAttrs (_: callPkg pkgs);
-
-  /* Gets the name for the default package using value set in root module or
-     derivation attrs.
-  */
-  defaultPkgName = root: pkg: root.name or pkg.pname or (parseDrvName pkg).name;
-
-  /* Merges elements of a list of sets recursively. Each element can optionally
-     be a function that takes the merged previous elements.
-  */
-  recUpdateSets = foldl (acc: x: recursiveUpdate acc ((ensureFn x) acc)) { };
-
-  isApp = x: (x ? type) && (x.type == "app") && (x ? program);
-
-  /* Turns app into an app attribute, if it is not already. Passes it pkgs if it
-     is a function.
-  */
-  mkApp = pkgs: app:
-    let
-      app' = callFn pkgs app;
-    in
-    if isApp app' then app'
-    else { type = "app"; program = "${app'}"; };
-
-  /* Makes cmd into a derivation for a flake's checks output. If it is not
-     already a derivation, makes one that runs cmd on the flake source and
-     depends on its success. Passes cmd pkgs if it is its a function.
-  */
-  mkCheck = pkgs: src: name: cmd:
-    let
-      cmd' = callFn pkgs cmd;
-    in
-    if pkgs.lib.isDerivation cmd' then cmd' else
-    pkgs.runCommand "check-${name}" { } ''
-      cp --no-preserve=mode -r ${src} src
-      cd src
-      ${cmd'}
-      touch $out
-    '';
-
-  /* Takes a packages set and a package and returns true if the package is
-     supported on the system for that packages set. If unknown, returns true.
-  */
-  supportedSystem = { lib, stdenv, ... }: pkg:
-    if pkg ? meta.platforms
-    then lib.meta.availableOn stdenv.hostPlatform pkg
-    else true;
-
-  systems = rec {
-    # Linux systems with binary caches.
-    linuxDefault = [
-      "x86_64-linux"
-      "aarch64-linux"
-    ];
-    # Linux systems supported as a host platform.
-    linuxAll = linuxDefault ++ [
-      "armv6l-linux"
-      "armv7l-linux"
-      "i686-linux"
-    ];
-  };
-
-  /* Creates flake outputs; takes the path of the flake and the root module.
-  */
-  mkFlake = src: root:
-    let
-      # These are passed to modules and non-system-dependent module attrs.
-      nonSysArgs = exports // {
-        args = nonSysArgs;
-        flakelite = exports;
-        root = root';
-        inherit src;
-        inherit (merged) inputs;
-        inherit (merged.inputs.nixpkgs) lib;
-      };
-
-      applyNonSysArgs = callFn nonSysArgs;
-
-      moduleAttrDefaults = {
-        inputs = { };
-        withOverlays = [ ];
-        nixpkgsConfig = { };
-        packages = { };
-        devTools = _: [ ];
-        shellHook = _: "";
-        devShells = _: { };
-        env = _: { };
-        overlays = { };
-        apps = _: { };
-        checks = _: { };
-        nixosModules = { };
-        nixosConfigurations = { };
-        homeModules = { };
-        homeConfigurations = { };
-        templates = { };
-        formatters = _: { };
-      };
-
-      normalizeModule = module:
-        let
-          module' = moduleAttrDefaults // module;
-        in
-        module' // {
-          withOverlays = (applyNonSysArgs module'.withOverlays)
-          ++ optional (module' ? withOverlay) module'.withOverlay;
-          nixpkgsConfig = applyNonSysArgs module'.nixpkgsConfig;
-          packages = (applyNonSysArgs module'.packages)
-          // optionalAttrs (module' ? package) {
-            default = module'.package;
-          };
-          devTools = filterArgs module'.devTools;
-          shellHook = filterArgs module'.shellHook;
-          devShells = fnMergeAttrs (filterArgs module'.devShells)
-            (_: optionalAttrs (module' ? devShell) {
-              default = module'.devShell;
-            });
-          env = filterArgs module'.env;
-          overlays = (applyNonSysArgs module'.overlays)
-          // optionalAttrs (module' ? overlay) {
-            default = module'.overlay;
-          };
-          apps = fnMergeAttrs (filterArgs module'.apps)
-            (_: optionalAttrs (module' ? app) {
-              default = module'.app;
-            });
-          checks = filterArgs module'.checks;
-          nixosModules = (applyNonSysArgs module'.nixosModules)
-          // optionalAttrs (module' ? nixosModule) {
-            default = module'.nixosModule;
-          };
-          nixosConfigurations = applyNonSysArgs module'.nixosConfigurations;
-          homeModules = (applyNonSysArgs module'.homeModules)
-          // optionalAttrs (module' ? homeModule) {
-            default = module'.homeModule;
-          };
-          homeConfigurations = applyNonSysArgs module'.homeConfigurations;
-          templates = (applyNonSysArgs module'.templates)
-          // optionalAttrs (module' ? template) {
-            default = module'.template;
-          };
-          formatters = filterArgs module'.formatters;
-        };
-
-      # Root module with autoloads, normalization, and additional attrs.
-      root' =
-        let
-          appliedRoot = applyNonSysArgs root;
-          nixDir = appliedRoot.nixDir or (src + /nix);
-          fullRoot = (autoImportAttrs nixDir rootAttrs attrAliases)
-            // appliedRoot;
-        in
-        normalizeModule fullRoot // {
-          modules = fullRoot.modules or
-            (pipe (removeAttrs root'.inputs [ "self" ]) [
-              (filterAttrs (_: v: v ? flakeliteModule))
-              (mapAttrsToList (_: v: v.flakeliteModule))
-            ]);
-          systems = applyNonSysArgs (fullRoot.systems or systems.linuxDefault);
-          perSystem = filterArgs (fullRoot.perSystem or { });
-          outputs = applyNonSysArgs (fullRoot.outputs or { });
-          inherit nixDir;
-        };
-
-      modules = [ baseModule ] ++ builtinModules ++ root'.modules;
-
-      # Merge result of all the modules.
-      merged = foldl mergeModules moduleAttrDefaults
-        ((map (m: normalizeModule (applyNonSysArgs m)) modules)
-          ++ [ root' ]);
-
-      # Returns package set for a system.
-      pkgsFor = system: import merged.inputs.nixpkgs {
-        inherit system;
-        config = merged.nixpkgsConfig;
-        overlays = merged.withOverlays ++ [
-          (final: _: callPkgs final merged.packages)
-        ];
-      };
-
-      # Attrset mapping systems to corresponding package sets.
-      systemPkgs = listToAttrs (map
-        (system: nameValuePair system (pkgsFor system))
-        root'.systems);
-
-      # Calls fn for each supported system. Fn should return an attrset whose
-      # attrs normally would have values in system attrs. Merges results into
-      # attrset with system attrs.
-      eachSystem = fn: foldAttrs mergeAttrs { } (map
-        (system: mapAttrs
-          (_: v: { ${system} = v; })
-          (fn systemPkgs.${system}))
-        root'.systems);
-
-      # Replaces the "default" attr in set with the default package name.
-      replaceDefault = set:
-        if set ? default
-        then (removeAttrs set [ "default" ]) //
-          { ${defaultPkgName root' set.default} = set.default; }
-        else set;
-    in
-    recUpdateSets [
-      (optionalAttrs (merged.packages != { }) ({
-        # Packages in overlay depend on withOverlays which are not in pkg set.
-        overlays.default = final: _: callPkgs
-          (final.appendOverlays merged.withOverlays)
-          (replaceDefault merged.packages);
-      } // eachSystem (pkgs: rec {
-        # Packages are generated in overlay on system pkgs; grab from there.
-        packages = filterAttrs (_: supportedSystem pkgs)
-          (intersectAttrs merged.packages pkgs);
-        checks = mapAttrs' (n: nameValuePair ("packages-" + n)) packages;
-      })))
-      (prev: optionalAttrs (merged.overlays != { }) ({
-        overlays = mergeOverlayAttrs (prev.overlays or { }) merged.overlays;
-      }))
-      (eachSystem ({ pkgs, lib, ... }:
-        optionalAttrs (merged.formatters pkgs != { }) rec {
-          formatter = pkgs.writeShellScriptBin "formatter" ''
-            PATH=${lib.makeBinPath (merged.devTools pkgs)}
-            for f in "$@"; do
-              if [ -d "$f" ]; then
-                ${pkgs.fd}/bin/fd "$f" -Htf -x "$0"
-              else
-                case "$(${pkgs.coreutils}/bin/basename "$f")" in
-                  ${toString (mapAttrsToList
-                    (n: v: "${n}) ${callFn pkgs v} \"$f\";;")
-                    (merged.formatters pkgs))}
-                esac
-              fi
-            done &>/dev/null
-          '';
-          checks.formatting = mkCheck pkgs src "formatting" ''
-            ${lib.getExe formatter} .
-            ${pkgs.diffutils}/bin/diff -qr ${src} . |\
-              sed 's/Files .* and \(.*\) differ/File \1 not formatted/g'
-          '';
-        }))
-      (eachSystem (pkgs:
-        let
-          checks = mapAttrs (mkCheck pkgs src) (merged.checks pkgs);
-        in
-        optionalAttrs (checks != { }) { inherit checks; }))
-      (eachSystem (pkgs:
-        let
-          apps = mapAttrs (_: mkApp pkgs) (merged.apps pkgs);
-        in
-        optionalAttrs (apps != { }) { inherit apps; }))
-      (optionalAttrs (merged.nixosModules != { }) {
-        inherit (merged) nixosModules;
-      })
-      (optionalAttrs (merged.nixosConfigurations != { }) {
-        inherit (merged) nixosConfigurations;
-        checks = recUpdateSets (mapAttrsToList
-          (n: v: {
-            ${v.config.nixpkgs.system}."nixos-${n}" =
-              v.config.system.build.toplevel;
-          })
-          merged.nixosConfigurations);
-      })
-      (optionalAttrs (merged.homeModules != { }) {
-        inherit (merged) homeModules;
-      })
-      (optionalAttrs (merged.homeConfigurations != { }) {
-        inherit (merged) homeConfigurations;
-        checks = recUpdateSets (mapAttrsToList
-          (n: v: {
-            ${v.config.nixpkgs.system}."home-${n}" = v.activationPackage;
-          })
-          merged.homeConfigurations);
-      })
-      (optionalAttrs (merged.templates != { }) {
-        inherit (merged) templates;
-      })
-      (prev: eachSystem ({ pkgs, system, mkShell, ... }: {
-        devShells = {
-          default = mkShell (merged.env pkgs // {
-            inputsFrom = optional (prev ? packages.${system}.default)
-              prev.packages.${system}.default;
-            packages = merged.devTools pkgs;
-            shellHook = merged.shellHook pkgs;
-          });
-        } // (callPkgs pkgs (merged.devShells pkgs));
-      }))
-      (eachSystem root'.perSystem)
-      (_: root'.outputs)
-    ];
 in
 {
-  lib = exports;
+  lib = flakelite;
   __functor = _: mkFlake;
 }

flake.lock

@@ -2,16 +2,16 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1680665430,
-        "narHash": "sha256-MTVhTukwza1Jlq2gECITZPFnhROmylP2uv3O3cSqQCE=",
+        "lastModified": 1692447944,
+        "narHash": "sha256-fkJGNjEmTPvqBs215EQU4r9ivecV5Qge5cF/QDLVn3U=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "5233fd2ba76a3accb5aaa999c00509a11fd0793c",
+        "rev": "d680ded26da5cf104dd2735a51e88d2d8f487b4d",
         "type": "github"
       },
       "original": {
         "id": "nixpkgs",
-        "ref": "nixos-22.11",
+        "ref": "nixos-unstable",
         "type": "indirect"
       }
     },

flake.nix

@@ -3,13 +3,10 @@
 # SPDX-License-Identifier: MIT
 
 {
-  inputs.nixpkgs.url = "nixpkgs/nixos-22.11";
+  inputs.nixpkgs.url = "nixpkgs/nixos-unstable";
   outputs = inputs:
     let
       flakelite = import ./. inputs;
     in
-    flakelite ./. {
-      nixDir = ./.;
-      outputs = _: flakelite;
-    };
+    flakelite ./. { outputs = flakelite; };
 }

packages/pre-commit-hook.nix

@@ -1,15 +0,0 @@
-{ writeShellApplication
-, coreutils
-, nix
-, git
-, gnutar
-}:
-writeShellApplication {
-  name = "pre-commit";
-  runtimeInputs = [ coreutils nix git gnutar ];
-  text = ''
-    TREE=$(mktemp -d)
-    git archive "$(git write-tree)" | tar -xC "$TREE"
-    nix flake check "$TREE"
-  '';
-}