lib: add mapNixDir{,1}

jeschli/5pkgs/simple/default.nix

@@ -15,10 +15,4 @@ let
     else override;
 in
 
-  listToAttrs
-    (map
-      (name: nameValuePair (removeSuffix ".nix" name)
-                           (callPackage (./. + "/${name}") {}))
-      (filter
-        (name: name != "default.nix" && !hasPrefix "." name)
-        (attrNames (readDir ./.))))
+  mapNixDir (path: callPackage path {}) ./.

krebs/5pkgs/haskell/default.nix

@@ -1,13 +1,6 @@
 with import <stockholm/lib>;
 let
-  overrides = self: super:
-    listToAttrs
-      (map
-        (name: nameValuePair (removeSuffix ".nix" name)
-                             (self.callPackage (./. + "/${name}") {}))
-        (filter
-          (name: name != "default.nix" && !hasPrefix "." name)
-          (attrNames (readDir ./.))));
+  overrides = self: super: mapNixDir (path: self.callPackage path {}) ./.;
 in
 self: super:
 {

krebs/5pkgs/simple/default.nix

@@ -15,10 +15,4 @@ let
     else override;
 in
 
-  listToAttrs
-    (map
-      (name: nameValuePair (removeSuffix ".nix" name)
-                           (callPackage (./. + "/${name}") {}))
-      (filter
-        (name: name != "default.nix" && !hasPrefix "." name)
-        (attrNames (readDir ./.))))
+  mapNixDir (path: callPackage path {}) ./.

lib/default.nix

@@ -44,6 +44,23 @@ let
 
     indent = replaceChars ["\n"] ["\n  "];
 
+    mapNixDir = f: x: {
+      list = foldl' mergeAttrs {} (map (mapNixDir1 f) x);
+      path = mapNixDir1 f x;
+    }.${typeOf x};
+
+    mapNixDir1 = f: dirPath:
+      listToAttrs
+        (map
+          (relPath: let
+            name = removeSuffix ".nix" relPath;
+            path = dirPath + "/${relPath}";
+          in
+            nameValuePair name (f path))
+          (filter
+            (name: name != "default.nix" && !hasPrefix "." name)
+            (attrNames (readDir dirPath))));
+
     # https://tools.ietf.org/html/rfc5952
     normalize-ip6-addr =
       let

tv/5pkgs/simple/default.nix

@@ -15,10 +15,4 @@ let
     else override;
 in
 
-  listToAttrs
-    (map
-      (name: nameValuePair (removeSuffix ".nix" name)
-                           (callPackage (./. + "/${name}") {}))
-      (filter
-        (name: name != "default.nix" && !hasPrefix "." name)
-        (attrNames (readDir ./.))))
+  mapNixDir (path: callPackage path {}) ./.