Split flake.nix into various modules

This will be useful during `om init` to ignore the template itself for #120
srid · Jul 23, 2024 · 60c8b39 · 60c8b39
1 parent 66c0fc7
commit 60c8b39
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Showing 4 changed files with 109 additions and 92 deletions.
diff --git a/flake.nix b/flake.nix
@@ -13,107 +13,22 @@
   outputs = inputs:
     inputs.flake-parts.lib.mkFlake { inherit inputs; } {
       systems = import inputs.systems;
-      imports = [
-        inputs.haskell-flake.flakeModule
-        inputs.treefmt-nix.flakeModule
-        inputs.fourmolu-nix.flakeModule
-      ];
 
-      # TODO: Remove this. Only relevant for github:srid/haskell-template
-      flake.templates.default = {
-        description = "A batteries-included Haskell project template for Nix";
-        path = builtins.path { path = inputs.self; };
-      };
+      # See ./nix/modules/*.nix for the modules that are imported here.
+      imports =
+        with builtins; map
+          (fn: ./nix/modules/${fn})
+          (attrNames (readDir ./nix/modules));
 
       perSystem = { self', lib, config, pkgs, ... }: {
-        # Our only Haskell project. You can have multiple projects, but this template
-        # has only one.
-        # See https://github.com/srid/haskell-flake/blob/master/example/flake.nix
-        haskellProjects.default = {
-          # To avoid unnecessary rebuilds, we filter projectRoot:
-          # https://community.flake.parts/haskell-flake/local#rebuild
-          projectRoot = builtins.toString (lib.fileset.toSource {
-            root = ./.;
-            fileset = lib.fileset.unions [
-              ./src
-              ./haskell-template.cabal
-              ./LICENSE
-              ./README.md
-            ];
-          });
-
-          # The base package set (this value is the default)
-          # basePackages = pkgs.haskellPackages;
-
-          # Packages to add on top of `basePackages`
-          packages = {
-            # Add source or Hackage overrides here
-            # (Local packages are added automatically)
-            /*
-            aeson.source = "1.5.0.0" # Hackage version
-            shower.source = inputs.shower; # Flake input
-            */
-          };
-
-          # Add your package overrides here
-          settings = {
-            /*
-            haskell-template = {
-              haddock = false;
-            };
-            aeson = {
-              check = false;
-            };
-            */
-          };
-
-          # Development shell configuration
-          devShell = {
-            hlsCheck.enable = false;
-          };
-
-          # What should haskell-flake add to flake outputs?
-          autoWire = [ "packages" "apps" "checks" ]; # Wire all but the devShell
-        };
-
-        # Auto formatters. This also adds a flake check to ensure that the
-        # source tree was auto formatted.
-        treefmt.config = {
-          projectRootFile = "flake.nix";
-
-          programs.fourmolu = {
-            enable = true;
-            package = config.fourmolu.wrapper;
-          };
-          programs.nixpkgs-fmt.enable = true;
-          programs.cabal-fmt.enable = true;
-          programs.hlint.enable = true;
-        };
-
-        fourmolu.settings = {
-          indentation = 2;
-          comma-style = "leading";
-          record-brace-space = true;
-          indent-wheres = true;
-          import-export-style = "diff-friendly";
-          respectful = true;
-          haddock-style = "multi-line";
-          newlines-between-decls = 1;
-          extensions = [ "ImportQualifiedPost" ];
-        };
-
-        # Default package & app.
-        packages.default = self'.packages.haskell-template;
-        apps.default = self'.apps.haskell-template;
-
         # Default shell.
         devShells.default = pkgs.mkShell {
           name = "haskell-template";
           meta.description = "Haskell development environment";
           # See https://community.flake.parts/haskell-flake/devshell#composing-devshells
           inputsFrom = [
-            config.haskellProjects.default.outputs.devShell
-            config.treefmt.build.devShell
+            config.haskellProjects.default.outputs.devShell # See ./nix/modules/haskell.nix
+            config.treefmt.build.devShell # See ./nix/modules/formatter.nix
           ];
           packages = with pkgs; [
             just

diff --git a/nix/modules/formatter.nix b/nix/modules/formatter.nix
@@ -0,0 +1,29 @@
+{
+  perSystem = { config, pkgs, ... }: {
+    # Auto formatters. This also adds a flake check to ensure that the
+    # source tree was auto formatted.
+    treefmt.config = {
+      projectRootFile = "flake.nix";
+
+      programs.fourmolu = {
+        enable = true;
+        package = config.fourmolu.wrapper;
+      };
+      programs.nixpkgs-fmt.enable = true;
+      programs.cabal-fmt.enable = true;
+      programs.hlint.enable = true;
+    };
+
+    fourmolu.settings = {
+      indentation = 2;
+      comma-style = "leading";
+      record-brace-space = true;
+      indent-wheres = true;
+      import-export-style = "diff-friendly";
+      respectful = true;
+      haddock-style = "multi-line";
+      newlines-between-decls = 1;
+      extensions = [ "ImportQualifiedPost" ];
+    };
+  };
+}
diff --git a/nix/modules/haskell.nix b/nix/modules/haskell.nix
@@ -0,0 +1,61 @@
+{ inputs, ... }:
+{
+  imports = [
+    inputs.haskell-flake.flakeModule
+  ];
+  perSystem = { self', lib, config, pkgs, ... }: {
+    # Our only Haskell project. You can have multiple projects, but this template
+    # has only one.
+    # See https://github.com/srid/haskell-flake/blob/master/example/flake.nix
+    haskellProjects.default = {
+      # To avoid unnecessary rebuilds, we filter projectRoot:
+      # https://community.flake.parts/haskell-flake/local#rebuild
+      projectRoot = builtins.toString (lib.fileset.toSource {
+        root = ../..;
+        fileset = lib.fileset.unions [
+          ../../src
+          ../../haskell-template.cabal
+          ../../LICENSE
+          ../../README.md
+        ];
+      });
+
+      # The base package set (this value is the default)
+      # basePackages = pkgs.haskellPackages;
+
+      # Packages to add on top of `basePackages`
+      packages = {
+        # Add source or Hackage overrides here
+        # (Local packages are added automatically)
+        /*
+            aeson.source = "1.5.0.0" # Hackage version
+            shower.source = inputs.shower; # Flake input
+            */
+      };
+
+      # Add your package overrides here
+      settings = {
+        /*
+            haskell-template = {
+              haddock = false;
+            };
+            aeson = {
+              check = false;
+            };
+            */
+      };
+
+      # Development shell configuration
+      devShell = {
+        hlsCheck.enable = false;
+      };
+
+      # What should haskell-flake add to flake outputs?
+      autoWire = [ "packages" "apps" "checks" ]; # Wire all but the devShell
+    };
+
+    # Default package & app.
+    packages.default = self'.packages.haskell-template;
+    apps.default = self'.apps.haskell-template;
+  };
+}
diff --git a/nix/modules/template.nix b/nix/modules/template.nix
@@ -0,0 +1,12 @@
+{ inputs, ... }:
+
+{
+  imports = [
+    inputs.treefmt-nix.flakeModule
+    inputs.fourmolu-nix.flakeModule
+  ];
+  flake.templates.default = {
+    description = "A batteries-included Haskell project template for Nix";
+    path = builtins.path { path = inputs.self; };
+  };
+}