Added _inherit_fields option to structs to inherit Fields from base c…

…lasses.

simplestruct/struct.py

@@ -119,6 +119,12 @@ def __prepare__(mcls, name, bases, **kargs):
     # Construct the _struct attribute on the new class.
     def __new__(mcls, clsname, bases, namespace, **kargs):
         fields = []
+        # If inheriting, gather fields from base classes.
+        if namespace.get('_inherit_fields', False):
+            for b in bases:
+                if isinstance(b, MetaStruct):
+                    fields += b._struct
+        # Gather fields from this class's namespace.
         for fname, f in namespace.copy().items():
             if not isinstance(f, Field):
                 continue

simplestruct/test_struct.py

@@ -164,6 +164,17 @@ def testPickleability(self):
 
         f3 = copy.deepcopy(f1)
         self.assertEqual(f3, f1)
+
+    def testInheritFields(self):
+        class Foo(Struct):
+            a = Field()
+        class Bar(Foo):
+            _inherit_fields = True
+            b = Field()
+
+        bar = Bar(1, 2)
+        self.assertEqual(bar.a, 1)
+        self.assertEqual(bar.b, 2)
 
 
 if __name__ == '__main__':