From 1e7ccb7acf70805693d6e8f4a4ef01d191804544 Mon Sep 17 00:00:00 2001
From: Kiana Sheibani <kiana.a.sheibani@gmail.com>
Date: Wed, 26 Nov 2025 16:53:32 -0500
Subject: [PATCH] refactor: improve `flake.nix` code

---
 flake.nix | 52 ++++++++++++++++++++++++++++------------------------
 1 file changed, 28 insertions(+), 24 deletions(-)

diff --git a/flake.nix b/flake.nix
index 51cee52..2ec1f3f 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,41 +2,45 @@
   description = "Hello World flake templates for various languages and build systems";
 
   outputs = { self, ... }:
-    let
+    with builtins; let
+      concatMapAttrs = func: attr:
+       foldl' (x: y: x // y) {} (map func attr);
+
+      # Template Aliases
+      # Used to pick default template for each language
       aliases = {
         bash = "bash_script_nixpkgs";
         fish = "fish_script_nixpkgs";
         python = "python_pyproject_nixpkgs_basic";
       };
 
-      # Get all project directories
+      # Get all subdirectories of the given path
+      # Returns [str]
       subdirs = dir:
-        let sub = __readDir dir;
-        in builtins.filter
-          (d: sub.${d} == "directory")
-          (builtins.attrNames sub);
-
-      concatMapAttrs = func: attr:
-        builtins.foldl' (x: y: x // y) {}
-          (builtins.map func attr);
+        let subd = readDir dir;
+        in filter (d: subd.${d} == "directory") (attrNames subd);
 
+      # Get all proper recursive subdirectories with flakes in them
+      # Returns [[str]] (list of subdirectory sequences, for processing)
       flakeSubdirs = dir:
-        builtins.concatMap (sub:
-          if builtins.pathExists /${dir}/${sub}/flake.nix then [ [ sub ] ] else
-            builtins.map (l: [ sub ] ++ l) (flakeSubdirs /${dir}/${sub}))
+        concatMap (subd:
+          if pathExists /${dir}/${subd}/flake.nix then [ [ subd ] ] else
+            map (l: [ subd ] ++ l) (flakeSubdirs /${dir}/${subd}))
           (subdirs dir);
+
+      generateDesc = subds:
+        "${head subds} template - ${concatStringsSep ", " (tail subds)}";
     in {
-      templates = concatMapAttrs (path: {
-        ${builtins.concatStringsSep "_" path} = {
-          description = "${builtins.head path} template - ${builtins.concatStringsSep
-            ", " (builtins.tail path)}";
-          path = builtins.filterSource
-            (path: type: builtins.baseNameOf path != "flake.lock")
-            (builtins.foldl' (dir: sub: /${dir}/${sub}) ./. path);
+      templates = concatMapAttrs (subds: {
+        ${concatStringsSep "_" subds} = {
+          description = generateDesc subds;
+          path = filterSource
+            (p: _: baseNameOf p != "flake.lock")
+            (foldl' (dir: subd: /${dir}/${subd}) ./. subds);
         };
-      }) (flakeSubdirs ./.) // builtins.mapAttrs (lang: def:
-        self.templates.${def} // {
-          description = "${lang} template";
-      }) aliases;
+      }) (flakeSubdirs ./.) // mapAttrs (from: to:
+        self.templates.${to} // {
+          description = generateDesc (filter (p: p != []) (split "_" to));
+        }) aliases;
     };
 }