FAST-Python

Famix AST representation for Python based on TreeSitter

• FAST-Python
  • Installation
  • Quick start
  • Documentation
  • Control flow graph
  • Local resolutions
  • Single Static Assignment (SSA)
  • Moose versions compatibility
  • TreeSitter python version compatibility
  • Python version compatibility
  • Contact

Installation

To install this project on your Pharo image, execute the following script:

Metacello new
	githubUser: 'moosetechnology' project: 'FAST-Python' commitish: 'main' path: 'src';
	baseline: 'FASTPython';
	load

To add this project to your baseline:

spec
	baseline: 'FASTPython'
	with: [ spec repository: 'github://moosetechnology/FAST-Python:main/src' ]

Note you can replace the #master by another branch such as #development or a tag such as #v1.0.0, #v1.? or #v1.2.? .

Quick start

In order to parse a chain of character or a file you can do this:

    FASTPythonImporter parse: 'if x > 0:
    if x < 10:
        1
    else:
        2
else:
    3'

Or

    FASTPythonImporter parseFile: myFile

Documentation

The best documentation to read about this project is located in Pharo Tree Sitter's repository here: https://github.com/Evref-BL/Pharo-Tree-Sitter/blob/main/resources/doc/fast_importer.md and here: https://github.com/Evref-BL/Pharo-Tree-Sitter/blob/main/resources/doc/ts_utilities.md

You can find the documentation on some analysis possible here: Analysis documentation.

Control flow graph

It is possible to get a control flow graph of your python entities like this:

FASTPythonCFGVisitor buildCFGOf: aModel allFunctionDefinitions first.

"or"

aModel allFunctionDefinitions first cfg

A CFG can be done on a function, method, class, module or lambda.

You can visualize it in the inspector as a visualization and you can also export your CFG as a mermaid visualization using #asMermaidScript

For more information check the analysis documentation linked above.

Local resolutions

It is possible to apply a local name resolution on a FAST-Python model by executing this piece of code:

FASTPythonLocalResolverVisitor resolve: model module "Can be any behavioral entity"

Once this is executed, all nodes resolved will be able to provide a #localDeclaration pointing to the declaration/first use of the entity. This local declaration also knows all the #localUses of the entity.

For more information check the analysis documentation linked above.

Single Static Assignment (SSA)

It is possible to build the SSA of a FAST-Python model like this:

It can be run like this:

FASTPythonSSAVisitor resolve: model module

Then we can ask to any node representing a variable access #ssaVersion. This version is able to tell us where are the read and write accesses of this particular version of the variable.

For more information check the analysis documentation linked above.

Moose versions compatibility

Version	Compatible Moose versions
v1.x.x	Moose 13

TreeSitter python version compatibility

TreeSitter python changed after the version 0.25 to remove expression statement for the produced tree. The parser do not work in 100% of the case for version <= 0.25. So if you have tests that are not passing, first check the version of tree-sitter-python you are using.

Python version compatibility

This importer should work for Python 2 and 3 (but Python 2 code has less test coverage).

Latest tested python version is 3.13.3. Features added after this release might not be taken into account.

Contact

If you have any questions or problems do not hesitate to open an issue or contact cyril (a) ferlicot.fr