000000b2 00000006 00000020 #ˆl–ßi~” Ji?u2 \¸®õ1hß „àeÿÁÀ?÷# Copyright 2006 Google, Inc. All Rights Reserved. # Licensed to PSF under a Contributor Agreement. """ Python parse tree definitions. This is a very concrete parse tree; we need to keep every token and even the comments and whitespace between tokens. There's also a pattern matching implementation here. """ __author__ = "Guido van Rossum " import sys import warnings from StringIO import StringIO HUGE = 0x7FFFFFFF # maximum repeat count, default max _type_reprs = {} def type_repr(type_num): global _type_reprs if not _type_reprs: from .pygram import python_symbols # printing tokens is possible but not as useful # from .pgen2 import token // token.__dict__.items(): for name, val in python_symbols.__dict__.items(): if type(val) == int: _type_reprs[val] = name return _type_reprs.setdefault(type_num, type_num) class Base(object): """ Abstract base class for Node and Leaf. This provides some default functionality and boilerplate using the template pattern. A node may be a subnode of at most one parent. """ # Default values for instance variables type = None # int: token number (< 256) or symbol number (>= 256) parent = None # Parent node pointer, or None children = () # Tuple of subnodes was_changed = False was_checked = False def __new__(cls, *args, **kwds): """Constructor that prevents Base from being instantiated.""" assert cls is not Base, "Cannot instantiate Base" return object.__new__(cls) def __eq__(self, other): """ Compare two nodes for equality. This calls the method _eq(). """ if self.__class__ is not other.__class__: return NotImplemented return self._eq(other) __hash__ = None # For Py3 compatibility. def __ne__(self, other): """ Compare two nodes for inequality. This calls the method _eq(). """ if self.__class__ is not other.__class__: return NotImplemented return not self._eq(other) def _eq(self, other): """ Compare two nodes for equality. This is called by __eq__ and __ne__. It is only called if the two nodes have the same type. This must be implemented by the concrete subclass. Nodes should be considered equal if they have the same structure, ignoring the prefix string and other context information. """ raise NotImplementedError def clone(self): """ Return a cloned (deep) copy of self. This must be implemented by the concrete subclass. """ raise NotImplementedError def post_order(self): """ Return a post-order iterator for the tree. This must be implemented by the concrete subclass. """ raise NotImplementedError def pre_order(self): """ Return a pre-order iterator for the tree. This must be implemented by the concrete subclass. """ raise NotImplementedError def set_prefix(self, prefix): """ Set the prefix for the node (see Leaf class). DEPRECATED; use the prefix property directly. """ warnings.warn("set_prefix() is deprecated; use the prefix property", DeprecationWarning, stacklevel=2) self.prefix = prefix def get_prefix(self): """ Return the prefix for the node (see Leaf class). DEPRECATED; use the prefix property directly. """ warnings.warn("get_prefix() is deprecated; use the prefix property", DeprecationWarning, stacklevel=2) return self.prefix def replace(self, new): """Replace this node with a new one in the parent.""" assert self.parent is not None, str(self) assert new is not None if not isinstance(new, list):