haxePackages: refactor to improve readability

pkgs/top-level/haxe-packages.nix

@@ -1,9 +1,6 @@
 { stdenv, lib, fetchzip, fetchFromGitHub, haxe, neko, jdk, mono }:
 
 let
-  self = haxePackages;
-  haxePackages = with self; {
-
   withCommas = lib.replaceStrings [ "." ] [ "," ];
 
   # simulate "haxelib dev $libname ."
@@ -20,12 +17,12 @@ let
     cp -dpR ${files} "$out/lib/haxe/${withCommas libname}/${withCommas version}/"
   '';
 
-    buildHaxeLib = {
-      libname,
-      version,
-      sha256,
-      meta,
-      ...
+  buildHaxeLib =
+    { libname
+    , version
+    , sha256
+    , meta
+    , ...
     } @ attrs:
     stdenv.mkDerivation (attrs // {
       name = "${libname}-${version}";
@@ -58,7 +55,8 @@ let
         description = throw "please write meta.description";
       } // attrs.meta;
     });
-
+in
+{
   format = buildHaxeLib {
     libname = "format";
     version = "3.5.0";
@@ -124,10 +122,12 @@ let
     meta.description = "Extern definitions for node.js 4.x";
   };
 
-    hxnodejs_6 = let
+  hxnodejs_6 =
+    let
       libname = "hxnodejs";
       version = "6.9.0";
-    in stdenv.mkDerivation {
+    in
+    stdenv.mkDerivation {
       name = "${libname}-${version}";
       src = fetchFromGitHub {
         owner = "HaxeFoundation";
@@ -143,5 +143,4 @@ let
         description = "Extern definitions for node.js 6.9";
       };
     };
-  };
-in self
+}