epita-coding-style

Filed under Project on January 7, 2025

A Python-based linting tool to validate C code against EPITA's coding standards

View on GitHub →

EPITA C/C++ Coding Style Checker

A fast C and C++ linter for EPITA coding style rules. Uses tree-sitter for robust AST-based parsing.

Features

  • C (.c, .h) and C++ (.cc, .hh, .hxx) support
  • 58 rules across file formatting, functions, exports, preprocessor, declarations, control flow, naming, and more
  • AST-based checks via tree-sitter (no regex hacks for structure)
  • clang-format integration with language-specific configs (C vs C++)
  • Configurable via TOML, presets, or CLI flags
  • Pre-commit hook support

Installation

pipx install epita-coding-style

Quick Start

epita-coding-style src/           # Check files/directories
epita-coding-style --list-rules   # List all rules with descriptions
epita-coding-style --show-config  # Show current configuration
epita-coding-style --help         # Full usage info

Example Output

$ epita-coding-style src/
src/rbtree.c:1:1: error: No blank lines at start of file [epita-file.spurious]

src/rbtree.c:307:1: error: 'rb_delete_cases' has 5 args (max 4) [epita-fun.arg.count]
static void rb_delete_cases(struct rb_node **node, struct rb_node **tmp,
src/rbtree.c:12:1: error: 2 exported globals (max 1) [epita-export.other]
src/rbtree.c:1:1: error: 36 lines need formatting [epita-format]

Files: 1  Major: 4  Minor: 0

Fix formatting: clang-format -i src/rbtree.c

Supported File Extensions

Language Source Header
C .c .h
C++ .cc .hh, .hxx

C++ files using .cpp / .hpp will be checked but flagged with a file.ext violation.

Configuration

Configuration is auto-detected from (in order):

  • .epita-style
  • .epita-style.toml
  • epita-style.toml
  • [tool.epita-coding-style] in pyproject.toml

Priority: CLI flags > config file > preset > defaults

Generate a Config File

epita-coding-style --show-config --no-color > .epita-style.toml

This outputs a complete, commented TOML config you can customize.

Presets

epita-coding-style --preset 42sh src/      # 40 lines, goto/cast allowed
epita-coding-style --preset noformat src/  # Same + skip clang-format

Example Config

# .epita-style.toml
max_lines = 40

[rules]
"keyword.goto" = false  # Allow goto
"cast" = false          # Allow casts

Or in pyproject.toml:

[tool.epita-coding-style]
max_lines = 40

[tool.epita-coding-style.rules]
"keyword.goto" = false

Limits

Setting Default (C) Default (C++) Description
max_lines 30 50 Max lines per function body
max_args 4 4 Max arguments per function
max_funcs 10 — Max exported functions per file (C only)
max_globals 1 — Max exported globals per file (C only)

Rules Overview

Use epita-coding-style --list-rules for the full list. Key categories:

C rules (enabled by default):

  • File — line endings, trailing whitespace, blank lines, file termination
  • Style — Allman brace style
  • Functions — length, argument count, (void) for empty params
  • Exports — max exported functions/globals per .c file
  • Preprocessor — include guards, # column, #endif comments, digraphs
  • Declarations — one per line, no VLAs
  • Control — no empty loop bodies
  • Strict — no goto, no explicit casts
  • Formatting — clang-format compliance

C++ rules (auto-enabled for .cc/.hh/.hxx files):

  • File — correct extensions (.cc/.hh/.hxx, not .cpp/.hpp)
  • Preprocessor — #pragma once, include order, no source includes, constexpr
  • Global — C++ casts, no malloc, nullptr, no extern "C", C++ headers, std:: functions
  • Naming — CamelCase classes/structs, lowercase namespaces with closing comments
  • Declarations — &/* next to type, explicit constructors, no VLAs
  • Control — switch default case, label padding, no empty loops
  • Writing — empty braces, single-expression braces, throw/catch rules, operator overloads, enum class, function length

clang-format

The format rule uses clang-format to check code formatting. Requires clang-format to be installed.

The checker uses language-specific configs:

  • C: looks for .clang-format-c, then .clang-format
  • C++: looks for .clang-format-cxx, then .clang-format

It searches from the file's directory up to root, falling back to the bundled EPITA configs.

To disable: set "format" = false in your config, or use --preset noformat.

Pre-commit Hook

# .pre-commit-config.yaml
repos:
  - repo: https://github.com/KazeTachinuu/epita-coding-style
    rev: v3.1.0
    hooks:
      - id: epita-coding-style
        args: [--preset, 42sh]  # optional

License

MIT