astor

What it is and what it does

astor is a library for reading, rewriting, and writing Python abstract syntax trees back to source code. It specializes in round-tripping ASTs—converting them back to readable Python without requiring the modified tree to be fully compileable or include line numbers and context information. The library also provides pretty-printing of AST structures and supports non-recursive tree walking, allowing you to visit nodes and their children on your own terms rather than through forced recursion.

The package has no runtime dependencies and runs on Python 2.7 and Python 3.4 and later. It is commonly used in code generation, refactoring tools, and AST analysis where you need to inspect or transform Python code programmatically and then output human-readable results. The library includes the astor.rtrip tool for comparing two source trees functionally after transformations like PEP 8 formatting.

Use it for:

• Generate readable Python code from modified ASTs in code generation or transpilation tools.
• Compare two Python source files for functional equivalence after automated transformations.
• Debug AST structures by pretty-printing them in a more readable format than the built-in ast module.
• Build refactoring or linting tools that need to output modified code back to source.
• Implement custom AST visitors that walk the tree non-recursively and rewrite nodes based on parent context.

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

astor converts Python abstract syntax trees (ASTs) back to readable source code and provides tools for AST manipulation, inspection, and non-recursive tree traversal.

Yes. astor is stable (Production/Stable status), has no dependencies, installs easily, carries no known vulnerabilities, and solves a real problem—converting ASTs back to readable code—that the Python standard library does not address well. The 2019 release date is offset by active repository maintenance and broad adoption (top 5000 packages). Install it if you need AST round-tripping or advanced tree inspection.

Install

astor on PyPI

pip install astor

uv add astor

poetry add astor

Installing astor

Before you install

Low friction: pure Python wheel with no runtime dependencies. Maintained actively as of 2026-02-17, though the latest release dates to 2019-12-10.

License in practice

BSD-3-Clause (permissive): you may use, modify, and distribute astor freely in commercial and private projects, provided you include the license notice.

Quickstart

pip install astor==0.8.1

import ast
import astor

code = "x = 1 + 2"
tree = ast.parse(code)
print(astor.to_source(tree))

Verify before relying

• Whether the 2019-12-10 release date reflects active maintenance or if the package is in maintenance-only mode despite recent commits.

Package facts

Evidence: astor-0.8.1-py2.py3-none-any.whl

Keywords: ast, codegen, PEP 8

Tags

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