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# -*- coding: utf-8 -*-
"""
sphinx.pycode.nodes
~~~~~~~~~~~~~~~~~~~
Parse tree node implementations.
:copyright: Copyright 2007-2014 by the Sphinx team, see AUTHORS.
:license: BSD, see LICENSE for details.
"""
class BaseNode(object):
"""
Node superclass for both terminal and nonterminal nodes.
"""
parent = None
def _eq(self, other):
raise NotImplementedError
def __eq__(self, other):
if self.__class__ is not other.__class__:
return NotImplemented
return self._eq(other)
def __ne__(self, other):
if self.__class__ is not other.__class__:
return NotImplemented
return not self._eq(other)
__hash__ = None
def get_prev_sibling(self):
"""Return previous child in parent's children, or None."""
if self.parent is None:
return None
for i, child in enumerate(self.parent.children):
if child is self:
if i == 0:
return None
return self.parent.children[i-1]
def get_next_sibling(self):
"""Return next child in parent's children, or None."""
if self.parent is None:
return None
for i, child in enumerate(self.parent.children):
if child is self:
try:
return self.parent.children[i+1]
except IndexError:
return None
def get_prev_leaf(self):
"""Return the leaf node that precedes this node in the parse tree."""
def last_child(node):
if isinstance(node, Leaf):
return node
elif not node.children:
return None
else:
return last_child(node.children[-1])
if self.parent is None:
return None
prev = self.get_prev_sibling()
if isinstance(prev, Leaf):
return prev
elif prev is not None:
return last_child(prev)
return self.parent.get_prev_leaf()
def get_next_leaf(self):
"""Return self if leaf, otherwise the leaf node that succeeds this
node in the parse tree.
"""
node = self
while not isinstance(node, Leaf):
assert node.children
node = node.children[0]
return node
def get_lineno(self):
"""Return the line number which generated the invocant node."""
return self.get_next_leaf().lineno
def get_prefix(self):
"""Return the prefix of the next leaf node."""
# only leaves carry a prefix
return self.get_next_leaf().prefix
class Node(BaseNode):
"""
Node implementation for nonterminals.
"""
def __init__(self, type, children, context=None):
# type of nonterminals is >= 256
# assert type >= 256, type
self.type = type
self.children = list(children)
for ch in self.children:
# assert ch.parent is None, repr(ch)
ch.parent = self
def __repr__(self):
return '%s(%s, %r)' % (self.__class__.__name__,
self.type, self.children)
def __str__(self):
"""This reproduces the input source exactly."""
return ''.join(map(str, self.children))
def _eq(self, other):
return (self.type, self.children) == (other.type, other.children)
# support indexing the node directly instead of .children
def __getitem__(self, index):
return self.children[index]
def __iter__(self):
return iter(self.children)
def __len__(self):
return len(self.children)
class Leaf(BaseNode):
"""
Node implementation for leaf nodes (terminals).
"""
prefix = '' # Whitespace and comments preceding this token in the input
lineno = 0 # Line where this token starts in the input
column = 0 # Column where this token tarts in the input
def __init__(self, type, value, context=None):
# type of terminals is below 256
# assert 0 <= type < 256, type
self.type = type
self.value = value
if context is not None:
self.prefix, (self.lineno, self.column) = context
def __repr__(self):
return '%s(%r, %r, %r)' % (self.__class__.__name__,
self.type, self.value, self.prefix)
def __str__(self):
"""This reproduces the input source exactly."""
return self.prefix + str(self.value)
def _eq(self, other):
"""Compares two nodes for equality."""
return (self.type, self.value) == (other.type, other.value)
def convert(grammar, raw_node):
"""Convert raw node to a Node or Leaf instance."""
type, value, context, children = raw_node
if children or type in grammar.number2symbol:
# If there's exactly one child, return that child instead of
# creating a new node.
if len(children) == 1:
return children[0]
return Node(type, children, context=context)
else:
return Leaf(type, value, context=context)
def nice_repr(node, number2name, prefix=False):
def _repr(node):
if isinstance(node, Leaf):
return "%s(%r)" % (number2name[node.type], node.value)
else:
return "%s(%s)" % (number2name[node.type],
', '.join(map(_repr, node.children)))
def _prepr(node):
if isinstance(node, Leaf):
return "%s(%r, %r)" % (number2name[node.type],
node.prefix, node.value)
else:
return "%s(%s)" % (number2name[node.type],
', '.join(map(_prepr, node.children)))
return (prefix and _prepr or _repr)(node)
class NodeVisitor(object):
def __init__(self, number2name, *args):
self.number2name = number2name
self.init(*args)
def init(self, *args):
pass
def visit(self, node):
"""Visit a node."""
method = 'visit_' + self.number2name[node.type]
visitor = getattr(self, method, self.generic_visit)
return visitor(node)
def generic_visit(self, node):
"""Called if no explicit visitor function exists for a node."""
if isinstance(node, Node):
for child in node:
self.visit(child)
|
