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Neomacs replaces Emacs’s C core with Rust and a GPU display engine

github.com 5 min read Editor score 6/10

Neomacs reimplements Emacs’s roughly 300,000-line C core in Rust, uses a GPU display engine, and checks behavior against GNU Emacs as a test oracle. The ambitious rewrite raises useful questions about compatibility and verification for developer tools.

What

Neomacs is a hard fork of GNU Emacs that reimplements its C core in Rust and uses a GPU display engine.

How

It checks rewritten subsystems against GNU Emacs as a test oracle and uses real-world configurations such as Doom Emacs as a daily test bed.

Why it matters

The compatibility contract lets engineers replace major internals while preserving existing configurations, packages, and user workflows.

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