A side-by-side diff tool for the terminal.
Written for fun after reading the diff chapters in Building Git [1]
Dependencies: meson, cmake, make and ninja. A C++20 compatible compiler.
Build using meson.
On POSIX platforms you can use the make wrapper to invoke meson and ninja.
$ make debug
$ make release
$ make test
$ ls -l out/{debug,release}/diffy
On Windows you can generate a Visual Studio solution.
$ meson setup --vsenv --backend vs2022 --buildtype=debug out/vs-debug
Test coverage is very incomplete. There's a few unit tests for testing some components. There's
also an integration test suite that verifies the core algorithms by generating unified diffs and
applying them with patch.
$ tests/testsuite.py out/release/diffy
The test cases are constructed from the git history of various files from different projects.
You can create new ones with
$ ./extras/git-extract-test-cases ../../path/to/git-repo/and/a/file.xx
The side-by-side view has mostly been tested visually.
Copy extras/diffy-git to somewhere in your $PATH. This wrapper script invokes
diffy as a difftool. It allows negative numbers similar to git show -2.
$ git diffy -2
[1] https://blog.jcoglan.com/2017/02/12/the-myers-diff-algorithm-part-1/