Добавить executor/visitor.py

executor/visitor.py

@@ -0,0 +1,46 @@
+__author__ = 'RemiZOffAlex'
+__email__ = 'remizoffalex@mail.ru'
+
+
+class Visitor:
+    def __init__(self, methods: dict = {}):
+        self.__methods = methods
+
+    def register(self, name, handler):
+        self.__methods[name] = handler
+
+    def visit(self, node, *args, **kwargs):
+        if 'kind' in node:
+            name = node['kind']
+        else:
+            raise ValueError('Node is empty')
+        method = self.__methods.get(name, self.__class__.generic_visit)
+        result = method(self, node, *args, **kwargs)
+        return result
+
+    def generic_visit(self, node, *args, **kwargs):
+        """Called if no explicit visitor function exists for a node."""
+        method = node['kind']
+        raise NotImplementedError('No visitor method {method} was defined for this expression: {node}'.format(
+            method=method,
+            node=node
+        ))
+
+    def __getattr__(self, name):
+        raise AttributeError('Вызван несуществующий метод {name}'.format(name=name))
+
+    def __getitem__(self, key):
+        method = self.__methods[key]
+        return method
+
+    def __iter__(self):
+        return iter(self.__methods)
+
+    def __len__(self):
+        return len(self.__methods)
+
+    def __delitem__(self, key):
+        del self.__methods[key]
+
+    def __repr__(self):
+        return repr(self.__methods)