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https://github.com/google/pasta
Library to refactor python code through AST manipulation.
https://github.com/google/pasta
Last synced: 12 days ago
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Library to refactor python code through AST manipulation.
- Host: GitHub
- URL: https://github.com/google/pasta
- Owner: google
- License: apache-2.0
- Created: 2017-11-28T22:48:53.000Z (almost 7 years ago)
- Default Branch: master
- Last Pushed: 2024-02-26T23:09:20.000Z (9 months ago)
- Last Synced: 2024-10-29T15:55:49.784Z (14 days ago)
- Language: Python
- Homepage:
- Size: 502 KB
- Stars: 342
- Watchers: 18
- Forks: 40
- Open Issues: 13
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
Awesome Lists containing this project
- awesome-codemods - **pasta** - code rewriting for Python using AST mutation instead of string templates (Libraries/Tools for refactoring / Debian)
README
# pasta: **P**ython **AST** **A**ugmentation
*This is still a work-in-progress; there is much more to do. Existing
functionality may not be perfect.*
## Mission
Enable python source code refactoring through AST modifications.
Sample use cases:
* Facilitate moving or renaming python modules by rewriting import statements.
* Refactor code to enforce a certain style, such as reordering function
definitions.
* Safely migrate code from one API to another.
## Design Goals
* **Symmetry**: Given any input source, it should hold that
`pasta.dump(pasta.parse(src)) == src`.
* **Mutability**: Any changes made in the AST are reflected in the code
generated from it.
* **Standardization**: The syntax tree parsed by pasta will not introduce new
nodes or structure that the user must learn.
## Python Version Support
Supports python `2.7` and up to `3.8`.
## Dependencies
`pasta` depends on [`six`](https://pypi.org/project/six/).
## Basic Usage
```python
import pasta
tree = pasta.parse(source_code)
# ... Augment contents of tree ...
source_code = pasta.dump(tree)
```
## Built-in Augmentations
Pasta includes some common augmentations out-of-the-box. These can be used as
building blocks for more complex refactoring actions.
*There will be more of these basic augmentations added over time. Stay tuned!*
### Rename an imported name
Rewrites references to an imported name, module or package. For some more
examples, see [`pasta/augment/rename_test.py`](pasta/augment/rename_test.py).
```python
# Rewrite references from one module to another
rename.rename_external(tree, 'pkg.subpkg.module', 'pkg.other_module')
# Rewrite references from one package to another
rename.rename_external(tree, 'pkg.subpkg', 'pkg.other_pkg')
# Rewrite references to an imported name in another module
rename.rename_external(tree, 'pkg.module.Query', 'pkg.module.ExecuteQuery')
```
## Known issues and limitations
* Changing the indentation level of a block of code is not supported. This is
not an issue for renames, but would cause problems for refactors like
extracting a method.
* `pasta` works under the assumption that the python version that the code is
written for and the version used to run pasta are the same. This is because
pasta relies on [`ast.parse`](https://docs.python.org/2/library/ast.html#ast.parse)
* Some python features are not fully supported, including `global`.
## Developing
This project uses
[`setuptools`](https://setuptools.readthedocs.io/en/latest/setuptools.html) to
facilitate testing and packaging.
```python
# Run all tests
python setup.py test
# Run a single test suite
python setup.py test -s pasta.base.annotate_test.suite
```
## Disclaimer
This is not an official Google product.