mopper 0.1.1

A small, fast, AST-based Python linter with zero runtime dependencies.

mopper

A lightweight Python linter built on the standard library's ast module, with zero runtime dependencies.

mopper doesn't aim to replace tools like Flake8 or Pylint. Instead, it focuses on a small set of practical checks that catch common mistakes such as unused imports, mutable default arguments, bare except clauses, unreachable code, and more.

Installation

pip install mopper

Usage

mopper path/to/file.py
mopper path/to/project/
mopper . --select B001,B003
mopper . --format json

Rules

Code	Check
B001	Unused import
B002	Bare except clause
B003	Mutable default argument
B004	Comparing to None, True, or False with == instead of is
B005	Unreachable code after return, raise, break, or continue
B006	Line longer than 100 characters

Why mopper?

mopper was built from scratch to understand how Python static analysis works internally using only the standard library. It demonstrates how a practical linter can be implemented with ast.NodeVisitor and a simple, extensible rule system.

License

MIT