AST Manipulation for Python Source Code Modification

Programmatically editing Python source code often involves reading and parsing the code into an Abstract Syntax Tree (AST). However, modifying the AST and writing back the modified code to generate a new source file can be challenging with standard Python modules like ast and compiler.

One solution to this problem is provided by the lib2to3 library, as used in the Pythoscope test case generator and the 2to3 tool for Python. lib2to3 preserves comments in the source code when parsing, transforming, and generating the modified code.

An alternative option is the rope project, which offers a more comprehensive approach to source code refactoring. rope includes support for various transform operations and refactorings.

For AST manipulation specifically, the ast module can be employed. However, while the ast module can transform ASTs, it is primarily intended for creating code objects.

Another option is the redbaron project, which provides a DSL for modifying Python source code in a concise and manageable way.

These tools allow you to programmatically modify Python source code through AST manipulation, enabling automated tasks such as mutation testing, code transformations, and refactoring.