py2cfg 0.3.2

Converts python source code to colorfor Control Flow Graphs (CFGs).

py2cfg

Python3 control flow graph generator

py2cfg is a package that can be used to produce control flow graphs (CFGs) for Python 3 programs. The CFGs it generates can be easily visualised with graphviz and used for static analysis. This analysis is the main purpose of the module.

Below is an example of a piece of code that generates the Fibonacci sequence and the CFG produced for it with py2cfg.

def fib():
    a, b = 0, 1
    while True:
        yield a
        a, b = b, a + b

fib_gen = fib()
for _ in range(10):
    next(fib_gen)

See ./examples/ for more examples

Installation

To install simply run

pip3 install ccfg

Usage

It can be used three ways:

Via CLI

The default command is ccfg:

ccfg <file.py>

This will create a _cfg.png file, which contains the colored cfg of the file.

Via wrapper

The cfg script present in the wrapper/ folder of this repository can be used to directly generate the CFG of some Python program and visualise it.

python3 ccfg path_to_my_code.py

Via import

To use py2cfg, simply import the module in your Python interpreter or program, and use the py2cfg.CFGBuilder class to build CFGs. For example, to build the CFG of a program defined in a file with the path ./example.py, the following code can be used:

from py2cfg import CFGBuilder

cfg = CFGBuilder().build_from_file('example', './example.py')

This returns the CFG for the code in ./example.py in the cfg variable. The first parameter of build_from_file is the desired name for the CFG, and the second one is the path to the file containing the source code. The produced CFG can then be visualised with:

cfg.build_visual('exampleCFG', 'pdf')

The first paramter of build_visual is the desired name for the DOT file produced by the method, and the second one is the format to use for the visualisation.

History

Note: this is a significantly re-worked fork of the following project:

• https://github.com/coetaur0/staticfg
• https://pypi.org/project/staticfg/