-            val = local_vars[m.group('in')]
-            if member == 'split("")':
-                return list(val)
-            if member == 'join("")':
-                return u''.join(val)
-            if member == 'length':
-                return len(val)
-            if member == 'reverse()':
-                return val[::-1]
-            slice_m = re.match(r'slice\((?P<idx>.*)\)', member)
-            if slice_m:
-                idx = self.interpret_expression(
-                    slice_m.group('idx'), local_vars, allow_recursion - 1)
-                return val[idx:]
+            arg_str = m.group('args')
+
+            if variable in local_vars:
+                obj = local_vars[variable]
+            else:
+                if variable not in self._objects:
+                    self._objects[variable] = self.extract_object(variable)
+                obj = self._objects[variable]
+
+            if arg_str is None:
+                # Member access
+                if member == 'length':
+                    return len(obj)
+                return obj[member]
+
+            assert expr.endswith(')')
+            # Function call
+            if arg_str == '':
+                argvals = tuple()
+            else:
+                argvals = tuple([
+                    self.interpret_expression(v, local_vars, allow_recursion)
+                    for v in arg_str.split(',')])
+
+            if member == 'split':
+                assert argvals == ('',)
+                return list(obj)
+            if member == 'join':
+                assert len(argvals) == 1
+                return argvals[0].join(obj)
+            if member == 'reverse':
+                assert len(argvals) == 0
+                obj.reverse()
+                return obj
+            if member == 'slice':
+                assert len(argvals) == 1
+                return obj[argvals[0]:]
+            if member == 'splice':
+                assert isinstance(obj, list)
+                index, howMany = argvals
+                res = []
+                for i in range(index, min(index + howMany, len(obj))):
+                    res.append(obj.pop(index))
+                return res
+
+            return obj[member](argvals)