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Copy pathnodevisitor.py
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85 lines (72 loc) · 2.78 KB
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###############################################################################
#
# Copyright (c) 2011 Ruslan Spivak
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
###############################################################################
class ASTVisitor(object):
"""Base class for custom AST node visitors.
Example:
>>> from slimit.parser import Parser
>>> from slimit.visitors.nodevisitor import ASTVisitor
>>>
>>> text = '''
... var x = {
... "key1": "value1",
... "key2": "value2"
... };
... '''
>>>
>>> class MyVisitor(ASTVisitor):
... def visit_Object(self, node):
... '''Visit object literal.'''
... for prop in node:
... left, right = prop.left, prop.right
... print 'Property value: {}'.format(right.value)
... # visit all children in turn
... self.visit(prop)
...
>>>
>>> parser = Parser()
>>> tree = parser.parse(text)
>>> visitor = MyVisitor()
>>> visitor.visit(tree)
Property value: "value1"
Property value: "value2"
"""
def visit(self, node):
method = 'visit_{}'.format(node.__class__.__name__)
return getattr(self, method, self.generic_visit)(node)
def generic_visit(self, node):
for child in node:
self.visit(child)
class NodeVisitor(object):
"""Simple node visitor."""
def visit(self, node):
"""Returns a generator that walks all children recursively."""
for child in node:
yield child
for subchild in self.visit(child):
yield subchild
def visit(node):
visitor = NodeVisitor()
for child in visitor.visit(node):
yield child