diff --git a/lib/writer.js b/lib/writer.js
index ba836373..d48e7410 100644
--- a/lib/writer.js
+++ b/lib/writer.js
@@ -35,16 +35,17 @@
             if (typeof it === "string") return opt.type(it); // XXX should maintain some context
             if (it.union) return "(" + it.idlType.map(type).join(" or ") + ")";
             var ret = "";
-            if (it.sequence) ret += "sequence<";
+            if (it.generic) ret += it.generic + "<";
+            else if (it.sequence) ret += "sequence<";
             ret += type(it.idlType);
-            if (it.array) {
+            if (it.array || it.generic === 'Array') {
                 for (var i = 0, n = it.nullableArray.length; i < n; i++) {
                     var val = it.nullableArray[i];
                     if (val) ret += "?";
                     ret += "[]";
                 }
             }
-            if (it.sequence) ret += ">";
+            if (it.generic || it.sequence) ret += ">";
             if (it.nullable) ret += "?";
 
             return ret;
@@ -142,6 +143,7 @@
         var field = function (it) {
             var ret = extended_attributes(it.extAttrs, curPea);
             curPea = "";
+            if (it.required) ret += "required ";
             ret += type(it.idlType) + " " + it.name;
             if (it["default"]) ret += " = " + const_value(it["default"]);
             ret += ";";
@@ -190,6 +192,44 @@
             }
             return ret + "};";
         };
+        var serializer = function(it) {
+            var ret = "serializer";
+            if (it.name) {
+              ret += " = " + it.name + ";";
+            } else if (it.patternList) {
+              ret += " = [ " + it.names.join(", ") + " ];";
+            } else if (it.patternMap) {
+              ret += " = { " + it.names.join(", ") + " };";
+            } else if (it.operation) {
+              ret += " " + operation(it);
+            } else {
+              ret += ";";
+            }
+            return ret;
+        };
+        var iterable = function(it) {
+          return "iterable<" + (it.idlType instanceof Array
+            ? it.idlType.map(type).join(", ")
+            : type(it.idlType)
+          ) + ">;";
+        };
+        var legacyiterable = function(it) {
+          return "legacyiterable<" + (it.idlType instanceof Array
+            ? it.idlType.map(type).join(", ")
+            : type(it.idlType)
+          ) + ">;";
+        };
+        var maplike = function(it) {
+          return (it.readonly ? "readonly " : "") + "maplike<" +
+            it.idlType.map(type).join(", ") + ">;";
+        };
+        var setlike = function(it) {
+          return (it.readonly ? "readonly " : "") + "setlike<" +
+            type(it.idlType) + ">;";
+        };
+        var callbackInterface = function(it) {
+          return 'callback ' + interface_(it);
+        };
         
         var table = {
             ws:                     literal
@@ -208,6 +248,12 @@
         ,   "implements":           implements_
         ,   callback:               callback
         ,   "enum":                 enum_
+        ,   serializer:             serializer
+        ,   iterable:               iterable
+        ,   legacyiterable:         legacyiterable
+        ,   maplike:                maplike
+        ,   setlike:                setlike
+        ,   "callback interface":   callbackInterface
         };
         var dispatch = function (it) {
             return table[it.type](it);