chore: modularize flake (#1440)

flake.nix

@@ -1,5 +1,4 @@
 # General TODOS:
-# - Extract into modules for better readability
 # - Add comments explaining the more terse parts of the flake.
 {
   description = "Flake for Neorg development and testing";
@@ -29,181 +28,21 @@
         "x86_64-darwin"
         "aarch64-darwin"
       ];
-      perSystem = {
-        config,
-        self',
-        inputs',
-        pkgs,
-        system,
-        lib,
-        ...
-      }: let
-        pkgs = import nixpkgs {
-          inherit system;
-          overlays = [
-            gen-luarc.overlays.default
-          ];
-        };
-        dependencies = builtins.fromJSON (builtins.readFile ./res/deps.json);
-        install-dependencies =
-          pkgs.runCommand "install-neorg-dependencies" {
-            nativeBuildInputs = with pkgs; [lua51Packages.luarocks wget];
-            outputHashAlgo = "sha256";
-            outputHashMode = "recursive";
-            outputHash = "sha256-SOsIgtmkXTKMZrKUHHzAf+XAshl/J7+DN9RFeLz+DDY=";
-          } ''
-            mkdir $PWD/home
-            export HOME=$PWD/home
-            mkdir -p $out/luarocks
 
-            ${lib.concatStrings (lib.mapAttrsToList (name: version: ''luarocks install --tree="$out/luarocks" --force-lock --local ${name} ${version}'' + "\n") dependencies)}
-          '';
-        luarc = pkgs.mk-luarc {};
-        luarc-with-dependencies =
-          luarc
-          // {
-            inherit (luarc) runtime;
-            inherit (luarc.Lua) diagnostics globals;
-            Lua.workspace = {
-              inherit (luarc.Lua.workspace) ignoreDir;
-              library = luarc.Lua.workspace.library ++ ["${install-dependencies}/luarocks/share/lua/5.1/"];
-            };
-          };
-      in {
-        formatter = pkgs.alejandra;
-
-        checks.type-check = git-hooks.lib.${system}.run {
-          src = ./lua;
-          hooks = {
-            lua-ls = {
-              enable = true;
-              settings.configuration = luarc-with-dependencies;
-            };
-          };
-        };
-
-        checks.pre-commit-check = git-hooks.lib.${system}.run {
-          src = self;
-          hooks = {
-            alejandra.enable = true;
-            luacheck.enable = true;
-            # stylua.enable = true;
-          };
-        };
-
-        packages.integration-test = let
-          kickstart-config =
-            pkgs.writeScript "kickstart.lua"
-            ''
-              -- Adapted from https://github.com/folke/lazy.nvim#-installation
-
-              -- Install lazy.nvim
-              local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
-              if not (vim.uv or vim.loop).fs_stat(lazypath) then
-                vim.fn.system({
-                  "git",
-                  "clone",
-                  "--filter=blob:none",
-                  "https://github.com/folke/lazy.nvim.git",
-                  "--branch=stable", -- latest stable release
-                  lazypath,
-                })
-              end
-              vim.opt.rtp:prepend(lazypath)
-
-              -- Set up both the traditional leader (for keymaps) as well as the local leader (for norg files)
-              vim.g.mapleader = " "
-              vim.g.maplocalleader = ","
-
-              require("lazy").setup({
-                {
-                  "rebelot/kanagawa.nvim", -- neorg needs a colorscheme with treesitter support
-                  config = function()
-                      vim.cmd.colorscheme("kanagawa")
-                  end,
-                },
-                {
-                  "nvim-treesitter/nvim-treesitter",
-                  build = ":TSUpdate",
-                  opts = {
-                    ensure_installed = { "c", "lua", "vim", "vimdoc", "query" },
-                    highlight = { enable = true },
-                  },
-                  config = function(_, opts)
-                    require("nvim-treesitter.configs").setup(opts)
-                  end,
-                },
-                {
-                    "vhyrro/luarocks.nvim",
-                    priority = 1000,
-                    config = true,
-                },
-                {
-                  "nvim-neorg/neorg",
-                  dependencies = { "luarocks.nvim" },
-                  config = function()
-                    require("neorg").setup {
-                      load = {
-                        ["core.defaults"] = {},
-                        ["core.concealer"] = {},
-                        ["core.dirman"] = {
-                          config = {
-                            workspaces = {
-                              notes = "~/notes",
-                            },
-                            default_workspace = "notes",
-                          },
-                        },
-                      },
-                    }
-
-                    vim.cmd.e("success")
-
-                    vim.wo.foldlevel = 99
-                    vim.wo.conceallevel = 2
-                  end,
-                }
-              })
-            '';
-        in
-          pkgs.writeShellApplication {
-            name = "neorg-integration-test";
+      _module.args = {inherit gen-luarc git-hooks;};
 
-            runtimeInputs = with pkgs; [neovim-unwrapped tree-sitter lua5_1 wget kickstart-config];
-
-            text = ''
-              export NVIM_APPNAME="nvim-neorg"
-
-              echo "* Hello World!" > example.norg
-
-              nvim --headless -u ${kickstart-config} example.norg -c wq
-
-              rm example.norg
-
-              if [ ! -f success ]; then
-                  echo "Integration test failed!"
-                  exit 1
-              fi
-
-              rm success
-            '';
-          };
-
-        devShells.default = pkgs.mkShell {
-          name = "neorg devShell";
+      imports = [
+        ./nix/overlays
+        ./nix/checks
+      ];
 
-          shellHook = ''
-            ln -fs ${pkgs.luarc-to-json luarc-with-dependencies} .luarc.json
-          '';
+      perSystem = {pkgs, ...}: {
+        formatter = pkgs.alejandra;
 
-          packages = with pkgs; [
-            lua-language-server
-            stylua
-            lua51Packages.luacheck
-            nil
-            lua5_1
-          ];
-        };
+        imports = [
+          ./nix/packages
+          ./nix/shells
+        ];
       };
     };
 }

nix/checks/default.nix

@@ -0,0 +1,34 @@
+{
+  self,
+  git-hooks,
+  ...
+}: {
+  perSystem = {
+    pkgs,
+    system,
+    ...
+  }: {
+    checks = {
+      type-check = git-hooks.lib.${system}.run {
+        src = "${self}/lua";
+
+        hooks = {
+          lua-ls = {
+            enable = true;
+            settings.configuration = pkgs.luarc-with-dependencies;
+          };
+        };
+      };
+
+      pre-commit-check = git-hooks.lib.${system}.run {
+        src = "${self}";
+
+        hooks = {
+          alejandra.enable = true;
+          luacheck.enable = true;
+          # stylua.enable = true;
+        };
+      };
+    };
+  };
+}

nix/overlays/default.nix

@@ -0,0 +1,28 @@
+{
+  self,
+  inputs,
+  gen-luarc,
+  ...
+}: {
+  perSystem = {
+    pkgs,
+    system,
+    ...
+  }: {
+    _module.args.pkgs = import inputs.nixpkgs {
+      inherit system;
+
+      overlays = [
+        gen-luarc.overlays.default
+
+        (final: prev: {
+          lib = prev.lib // import ./lib.nix {inherit pkgs;};
+
+          # NOTE: I would have used callPackage for easy overriding, but
+          # this changes the type and *-to-json fails later. To be figured out.
+          luarc-with-dependencies = final.lib.callPackageNoOverridable ./luarc.nix {inherit self;};
+        })
+      ];
+    };
+  };
+}

nix/overlays/lib.nix

@@ -0,0 +1,12 @@
+{pkgs}: rec {
+  callPackageNoOverridableWith = originalAttrs: fun: additionalAttrs: let
+    f =
+      if pkgs.lib.isFunction fun
+      then fun
+      else import fun;
+    attrs = builtins.intersectAttrs (pkgs.lib.functionArgs f) originalAttrs;
+  in
+    f (attrs // additionalAttrs);
+
+  callPackageNoOverridable = callPackageNoOverridableWith pkgs;
+}

nix/overlays/luarc.nix

@@ -0,0 +1,35 @@
+{
+  lib,
+  self,
+  mk-luarc,
+  runCommand,
+  lua51Packages,
+  wget,
+}: let
+  luarc = mk-luarc {};
+
+  dependencies = builtins.fromJSON (builtins.readFile "${self}/res/deps.json");
+
+  install-dependencies =
+    runCommand "install-neorg-dependencies" {
+      nativeBuildInputs = [lua51Packages.luarocks wget];
+      outputHashAlgo = "sha256";
+      outputHashMode = "recursive";
+      outputHash = "sha256-SOsIgtmkXTKMZrKUHHzAf+XAshl/J7+DN9RFeLz+DDY=";
+    } ''
+      mkdir $PWD/home
+      export HOME=$PWD/home
+      mkdir -p $out/luarocks
+
+      ${lib.concatStrings (lib.mapAttrsToList (name: version: ''luarocks install --tree="$out/luarocks" --force-lock --local ${name} ${version} '' + "\n") dependencies)}
+    '';
+in
+  luarc
+  // {
+    inherit (luarc) runtime;
+    inherit (luarc.Lua) diagnostics globals;
+    Lua.workspace = {
+      inherit (luarc.Lua.workspace) ignoreDir;
+      library = luarc.Lua.workspace.library ++ ["${install-dependencies}/luarocks/share/lua/5.1/"];
+    };
+  }

nix/packages/default.nix

@@ -0,0 +1,3 @@
+{pkgs, ...}: {
+  packages.integration-test = pkgs.callPackage ./integration-test.nix {};
+}