Built-in JSON support

src/macros.py

Index: src/macros.py
diff --git a/src/macros.py b/src/macros.py
index d78ecd94d19f3e29433cdc06418a3f4972a7c102..ebfd816a01c155ad63bed778a63a975cfb5c4908 100644
--- a/src/macros.py
+++ b/src/macros.py
@@ -84,6 +84,8 @@ macro IS_BOOLEAN(arg)           = (typeof(arg) === 'boolean');
 macro IS_REGEXP(arg)            = %HasRegExpClass(arg);
 macro IS_ARRAY(arg)             = %HasArrayClass(arg);
 macro IS_DATE(arg)              = %HasDateClass(arg);
+macro IS_NUMBER_WRAPPER(arg)    = %HasNumberClass(arg);
+macro IS_STRING_WRAPPER(arg)    = %HasStringClass(arg);
 macro IS_ERROR(arg)             = (%ClassOf(arg) === 'Error');
 macro IS_SCRIPT(arg)            = (%ClassOf(arg) === 'Script');
 macro FLOOR(arg)                = %Math_floor(arg);