LibCST
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A concrete syntax tree parser and serializer library for Python that preserves many aspects of Python's abstract syntax tree
Codemod to convert typing.Union and typing.Optional to [PEP 604](https://www.python.org/dev/peps/pep-0604/) syntax and add `__future__` as required.
for a function like: ```python def fun(arg): pass ``` the fully qualified name for `arg` will be `fun..arg`, but for any call to the function that chooses to call it...
``` class X: import random a = [random.lol for _ in ()] ``` `random` here is used by the class body, but gets removed by the codemod. This might be...
One consequence of the issue mentioned [here](https://github.com/Instagram/LibCST/pull/269#issuecomment-604640756), where CSTTransformer always replaces nodes, is that methods that rely on nodes-by-identity become harder to use in bulk. For example, I'm trying to...
In some lint or codemod use cases, we want to know the super classes of a class to see if it's inherited from a specific class in order to enforce...
`f"{a or ""}"` this is invalid syntax but LibCST handles it and renders the invalid code. We can either: - automatically escape the string quotes in the inner expression. -...
`ast` and libcst looks similar but different in many design details. To make it more clear and prevent confusion for users familiar with ast (I'm one of them), it worth...
Is it possible to parse code that has syntax errors in part of the code? I'd like to refactor code that might still be incomplete (and this, might have syntax...
While working on my [`shed` autoformatter](https://github.com/Zac-HD/shed/), which includes some libcst-based passes, [Hypothesmith](https://github.com/Zac-HD/hypothesmith) uncovered a bug: https://github.com/Instagram/LibCST/blob/c22ed6a4c67e5f16f0b928ca8a0c2944056eb216/libcst/_parser/types/config.py#L20 For example, `'class A:\n\x0c pass\n'` is a valid class-declaration. It can even be parsed...
This appears to be legal syntax (no space before `as`), found in cpython's `test/test_importlib/source/test_file_loader.py` by accident: ``` with f()as g: pass ```
