Likewise: A Diffing Library

This crate is a fork of similar library, which, as of 11/9/25, is rather inactive.

Likewise is a dependency free crate for Rust that implements different diffing algorithms and high level interfaces for it. It is based on the pijul implementation of the Patience algorithm and inherits some ideas from there. It also incorporates the Myers' diff algorithm which was largely written by Brandon Williams. This library was built for the insta snapshot testing library.

use likewise::{ChangeTag, TextDiff};

fn main() {
    let diff = TextDiff::from_lines(
        "Hello World\nThis is the second line.\nThis is the third.",
        "Hallo Welt\nThis is the second line.\nThis is life.\nMoar and more",
    );

    for change in diff.iter_all_changes() {
        let sign = match change.tag() {
            ChangeTag::Delete => "-",
            ChangeTag::Insert => "+",
            ChangeTag::Equal => " ",
        };
        print!("{}{}", sign, change);
    }
}

Screenshot

What's in the box?

• Myers' diff
• Patience diff
• Hunt–McIlroy / Hunt–Szymanski LCS diff
• Diffing on arbitrary comparable sequences
• Line, word, character and grapheme level diffing
• Text and Byte diffing
• Unified diff generation

Related Projects

• similar
• insta snapshot testing library
• similar-asserts assertion library

License and Links

• Documentation
• Issue Tracker
• Examples
• License: Apache-2.0