Fix Mozilla AST import of arrays with holes

lib/mozilla-ast.js

@@ -163,6 +163,20 @@
                             end   : my_end_token(M),
                             name  : M.name
                         });
+        },
+        ArrayExpression: function (M) {
+            var start = my_start_token(M);
+            var end = my_end_token(M);
+            return new AST_Array({
+                start: start,
+                end: end,
+                elements: M.elements.map(function (E) {
+                    return E ? from_moz(E) : new AST_Hole({
+                        start: start,
+                        end: end
+                    });
+                })
+            });
         }
     };
 
@@ -199,7 +213,6 @@
     map("CatchClause", AST_Catch, "param>argname, body%body");
 
     map("ThisExpression", AST_This);
-    map("ArrayExpression", AST_Array, "elements@elements");
     map("FunctionExpression", AST_Function, "id>name, params@argnames, body%body");
     map("BinaryExpression", AST_Binary, "operator=operator, left>left, right>right");
     map("LogicalExpression", AST_Binary, "operator=operator, left>left, right>right");
@@ -208,6 +221,13 @@
     map("NewExpression", AST_New, "callee>expression, arguments@args");
     map("CallExpression", AST_Call, "callee>expression, arguments@args");
 
+    def_to_moz(AST_Array, function To_Moz_ArrayExpression(M) {
+         return {
+             type: "ArrayExpression",
+             elements: M.elements.map(to_moz)
+         }
+    });
+
     def_to_moz(AST_Directive, function To_Moz_Directive(M) {
         return {
             type: "ExpressionStatement",