mr-proper

0.0.7 · active · verified Wed Apr 15

Mr-proper is a static Python code analyzer that aims to identify whether functions are 'pure' or not, and to explain the reasons behind its conclusions. It's a highly experimental library with known edge cases, and its definition of purity is specific to its implementation. The latest version is 0.0.7, released in October 2021, indicating an irregular release cadence.

Warnings

gotcha The library is explicitly stated as 'very experimental and has a lot of edge cases'. Functions marked as pure might not be strictly pure by other definitions, though they are generally cleaner. Rely on its findings with caution.
Fix: Thoroughly review code flagged as pure and understand `mr-proper`'s specific purity criteria. Do not solely rely on the tool for correctness without human review.
breaking The PyPI package name is `mr-proper` (with a hyphen), but the import statement requires `mr_propper` (with an underscore and a double 'p'). Using `import mr_proper` will result in an `ImportError`.
Fix: Always use `from mr_propper.utils import is_function_pure` or `import mr_propper` when importing.
gotcha The command-line interface (CLI) for `mr-proper` currently does not support checking directories recursively; it only accepts individual Python file paths.
Fix: To check multiple files or a project, you must iterate through files yourself or integrate the programmatic API into a custom script.
gotcha The project's activity has been low, with the last release in October 2021. This might imply slower responses to issues, potential unaddressed bugs, or a lack of new features.
Fix: Consider the maintenance status when planning long-term adoption. Review the GitHub issues and pull requests to gauge current community activity and maintainer responsiveness.

Install

pip install mr-proper Install latest version

Imports

is_function_pure
wrong:
```
from mr_proper.utils import is_function_pure
```
correct:
```
from mr_propper.utils import is_function_pure
```
The PyPI package is 'mr-proper', but the import path uses 'mr_propper' (double 'p'). Importing from 'mr_proper' will result in an ImportError.

Quickstart

This quickstart demonstrates how to use `mr-proper` programmatically by parsing an AST node (a function definition) and checking its purity using `is_function_pure`. It shows both a pure and a non-pure function example.

import ast
from mr_propper.utils import is_function_pure

# Example of a pure function
func_def_pure = ast.parse('''
def add_one(n: int) -> int:
    return n + 1
''').body[0]

is_pure, errors = is_function_pure(func_def_pure, with_errors=True)
print(f"'add_one' is pure: {is_pure}, Errors: {errors}")

# Example of a non-pure function
func_def_not_pure = ast.parse('''
def print_amount_of_users(users_qs: list) -> None:
    print(f'Current amount of users is {len(users_qs)}')
''').body[0]

is_pure, errors = is_function_pure(func_def_not_pure, with_errors=True)
print(f"'print_amount_of_users' is pure: {is_pure}, Errors: {errors}")

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