Welcome to the AST Unparser documentation!

An AST unparser for Python.

This is a factored out version of unparse found in the Python source distribution; under Demo/parser in Python 2 and under Tools/parser in Python 3.

Basic example:

import inspect
import ast
import astunparse

# get back the source code

# get a pretty-printed dump of the AST

This library is single-source compatible with Python 2.6 through Python 3.5. It is authored by the Python core developers; I have simply merged the Python 2.7 and the Python 3.5 source and test suites, and added a wrapper. This factoring out is to provide a library implementation that supports both versions.

Added to this is a pretty-printing dump utility function.

The test suite both runs specific tests and also roundtrips much of the standard library.

Extensions and Alternatives

Similar projects include:

None of these roundtrip much of the standard library and fail several of the basic tests in the test_unparse test suite.

This library uses mature and core maintained code instead of trying to patch existing libraries. The unparse and the test_unparse modules are under the PSF license.

Extensions include:

  • typed-astunparse: extends astunparse to support type annotations.


  • unparses Python AST.
  • pretty-prints AST.

Indices and tables