initial(ish) commit

lib/modules.nix

@@ -0,0 +1,54 @@
+{ self, lib, ... }:
+
+let
+  inherit (builtins) attrValues readDir pathExists concatLists;
+  inherit (lib) id mapAttrsToList filterAttrs hasPrefix hasSuffix nameValuePair removeSuffix;
+  inherit (self.attrs) mapFilterAttrs;
+in
+rec {
+  mapModules = dir: fn:
+    mapFilterAttrs
+      (n: v:
+        v != null &&
+        !(hasPrefix "_" n))
+      (n: v:
+        let path = "${toString dir}/${n}"; in
+        if v == "directory" && pathExists "${path}/default.nix"
+        then nameValuePair n (fn path)
+        else if v == "regular" &&
+          n != "default.nix" &&
+          hasSuffix ".nix" n
+        then nameValuePair (removeSuffix ".nix" n) (fn path)
+        else nameValuePair "" null)
+      (readDir dir);
+
+  mapModules' = dir: fn:
+    attrValues (mapModules dir fn);
+
+  mapModulesRec = dir: fn:
+    mapFilterAttrs
+      (n: v:
+        v != null &&
+        !(hasPrefix "_" n))
+      (n: v:
+        let path = "${toString dir}/${n}"; in
+        if v == "directory"
+        then nameValuePair n (mapModulesRec path fn)
+        else if v == "regular" && n != "default.nix" && hasSuffix ".nix" n
+        then nameValuePair (removeSuffix ".nix" n) (fn path)
+        else nameValuePair "" null)
+      (readDir dir);
+
+  mapModulesRec' = dir: fn:
+    let
+      dirs =
+        mapAttrsToList
+          (k: _: "${dir}/${k}")
+          (filterAttrs
+            (n: v: v == "directory" && !(hasPrefix "_" n))
+            (readDir dir));
+      files = attrValues (mapModules dir id);
+      paths = files ++ concatLists (map (d: mapModulesRec' d id) dirs);
+    in
+    map fn paths;
+}