astmonkey

astmonkey is a set of tools to play with Python AST.

Installation

You can install astmonkey from PyPI:

$ pip install astmonkey

If you want to have latest changes you should clone this repository and use setup.py:

$ git clone https://github.com/mutpy/astmonkey.git
$ cd astmonkey
$ python setup.py install

visitors.SourceGeneratorNodeVisitor

This visitor allow AST to Python code generation. It was originally written by Armin Ronacher (2008, license BSD) as codegen.py module. astmonkey version fixes few bugs and it has good code coverage.

Example usage:

import ast
from astmonkey import visitors

code = 'x = (y + 1)'
node = ast.parse(code)
generated_code = visitors.to_source(node)

assert(code == generated_code)

transformers.ParentChildNodeTransformer

This transformer adds few fields to every node in AST:

• parent - link to parent node,
• parents - list of all parents (only ast.expr_context nodes have more than one parent node, in other causes this is one-element list),
• parent_field - name of field in parent node including child node,
• parent_field_index - parent node field index, if it is a list.
• children - link to children nodes.

Example usage:

import ast
from astmonkey import transformers

node = ast.parse('x = 1')
node = transformers.ParentChildNodeTransformer().visit(node)

assert(node == node.body[0].parent)
assert(node.body[0].parent_field == 'body')
assert(node.body[0].parent_field_index == 0)
assert(node.body[0] in node.children)

visitors.GraphNodeVisitor

This visitor creates Graphviz graph from Python AST (via pydot). Before you use GraphNodeVisitor you need to add parents links to tree nodes (with ParentChildNodeTransformer).

Example usage:

import ast
from astmonkey import visitors, transformers

node = ast.parse('def foo(x):\n\treturn x + 1')
node = transformers.ParentChildNodeTransformer().visit(node)
visitor = visitors.GraphNodeVisitor()
visitor.visit(node)

visitor.graph.write_png('graph.png')

Produced graph.png (you need to have installed graphviz binaries if you want generate images):

utils.is_docstring

This routine checks if target node is a docstring. Before you use is_docstring you need to add parents links to tree nodes (with ParentChildNodeTransformer).

Example usage:

import ast
from astmonkey import utils, transformers

node = ast.parse('def foo(x):\n\t"""doc"""')
node = transformers.ParentChildNodeTransformer().visit(node)

docstring_node = node.body[0].body[0].value
assert(not utils.is_docstring(node))
assert(utils.is_docstring(docstring_node))

License

Copyright [2013] [Konrad Hałas]

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.