feat: Implement transpiler ASTx to Python String via ASTx to Python AST

[nagajaideep]

This PR refactors the python_to_ast.py module to align with the mentor's architecture for AST-based transpilation.
It removes circular dependencies, introduces a new module for string generation, and ensures a clean separation of concerns between AST conversion and string generation.

Changes Made:

1. Fixed Circular Dependency in python_to_ast.py:

   • Removed the circular import from astx_transpilers.python_string in the _convert_using_unparse method.
   • Replaced it with a fallback logic returning ast.Constant or ast.Name nodes.
   • Ensured the file is self-contained and only handles ASTx → Python AST conversion.

2. Created New python_string_new.py:

   • Implements the mentor’s design for string generation.
   • Uses ASTxPythonASTTranspiler from python_to_ast.py internally.
   • Flow: ASTx Node → ASTxPythonASTTranspiler → Python AST → ast.unparse() → String.
   • Maintains backward compatibility with indent handling.

3. Added test_new_implementation.py:

   • Tests the correctness of the new implementation.

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How to test these changes

For Direct AST Output (ASTx → Python AST):

from astx_transpilers.python_to_ast import ASTxPythonASTTranspiler
transpiler = ASTxPythonASTTranspiler()
ast_node = transpiler.visit(astx_node)  # Returns Python AST

For String Output (ASTx → Python Source Code):

from astx_transpilers.python_string_new import ASTxPythonTranspiler
transpiler = ASTxPythonTranspiler()
code_string = transpiler.visit(astx_node)  # Returns Python source code

Run Tests:

pytest -v libs/astx-transpilers/tests/test_new_implementation.py

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Pull Request checklists

Note:

• Share updated images of the graph representation of the new ASTx node
  proposed in this PR, in both image and ASCII formats. For more
  information, check this Google Colab notebook:
  https://colab.research.google.com/drive/1xXwHmOMkJKFSmhRvn4WYfSAsdDzMnawf?usp=sharing

This PR is a:

• bug-fix
• new feature
• maintenance

About this PR:

• it includes tests.
• the tests are executed on CI.
• the tests generate log file(s) (path).
• pre-commit hooks were executed locally.
• this PR requires a project documentation update.

Author's checklist:

• I have reviewed the changes and it contains no misspelling.
• The code is well commented, especially in the parts that contain more
  complexity.
• New and old tests passed locally.

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Additional information

Benefits of the Refactor:

• Single Source of Truth: Only python_to_ast.py handles ASTx → Python AST conversion.
• No Circular Dependencies: Clean import hierarchy.
• Reusability: AST output can be used for multiple purposes.
• Maintainability: Changes only need to be made in one place.
• Leverages Python's Tools: Uses ast.unparse() for consistent string generation.
• Modular Design: Clear separation between AST conversion and string generation.

---

## Reviewer's Checklist

- [ ] I managed to reproduce the problem locally from the `main` branch
- [ ] I managed to test the new changes locally
- [ ] I confirm that the issues mentioned were fixed/resolved .

[xmnlab]

thanks for working on that @nagajaideep
in general looks pretty good .. I will take a bit more time to review it again soon

[xmnlab]

@nagajaideep you shouldn't remove this file .. because this is the way we test the transpiler .. probably you should update the tests .. but it should be something similart:

transpile an astx node, and check the string if that makes sense

[xmnlab]

@nagajaideep could you please rebase your branch on top of the upstream main?

[nagajaideep]

Yes @xmnlab will rebase it and include the test_python_string.py file in the upcoming commit and fix those errors and give you an update