cargo-wrap-comments

A Rust command-line tool that formats source code comments to wrap long lines at a specified width. This does what rustfmt should do.

Features

• Wraps long comments to a configurable width (default: 100 characters)
• Reads max_width from .rustfmt.toml or rustfmt.toml if --max-width is not specified
• Combines consecutive comment lines before wrapping
• Supports Rust comment styles: //, ///, //!
• Preserves indentation, comment markers, and blank comment lines
• Respects hierarchical markers (#, *, -, 1., A., a.), back-tick quoted text, and code blocks
• Glob pattern support for processing multiple files
• Stdin/stdout mode when no files are specified
• Check mode for previewing changes without modifying files

Installation

cargo install cargo-wrap-comments

From source

cargo build --release

The binary will be at target/release/cargo-wrap-comments.

Usage

The tool can be run as a standalone command or as a Cargo subcommand:

# As a cargo subcommand
cargo wrap-comments src/main.rs

# As a standalone command
cargo-wrap-comments src/main.rs

# Format comments in multiple files with glob patterns
cargo wrap-comments "src/**/*.rs"

# Set custom width
cargo wrap-comments --max-width 80 src/main.rs

# Preview changes without modifying files
cargo wrap-comments --check src/main.rs

# Read from stdin, write to stdout
cat src/main.rs | cargo wrap-comments
cargo wrap-comments < src/main.rs

Options

Comment Combining Rules

Consecutive comment lines are combined before wrapping when ALL of these are true:

1. Same comment marker (//, ///, or //!)
2. Same indentation level
3. Neither line is blank
4. The next line does not start with a hierarchical marker: #, *, -, ```, 1., A., a.
5. The current line does not contain a code fence marker (```)
6. The current line does not start with # (markdown heading lines are not combined with the text that follows)

Width Resolution

The line width is resolved in this order:

1. --max-width N on the command line
2. max_width from .rustfmt.toml or rustfmt.toml, searching from the current directory up to $HOME
3. Default: 100

The search stops at the first config file found. If it exists but has no max_width, the default is used.

Exit Codes

• 0 — success
• 1 — one or more errors occurred (missing files, processing failures)