The Egison Programming Language

Egison is the world's first programming language that realized non-linear pattern-matching with backtracking.
We can directly represent pattern-matching against lists, multisets, sets, trees, graphs and any kind of data types.
Egison makes programming dramatically simple!

Online Egison Tutorial! Egison Cheat Sheet More Demonstrations »

What's New

Egison 3.3.4 is the latest version.

View More on Twitter ChangeLog on GitHub


Egison proposes a new paradigm pattern-matching-oriented. The combination of all of the following features enables intuitive powerful pattern-matching.

  • Modularization of the way of pattern-matching
  • Pattern-matching with backtracking
  • Non-linear patterns with lexical scoping

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Pattern-matching against ...

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We aim intuitive representation of algorithms and formalization of human recognitions.
We believe this is the shortest way to the artificial intelligence.


Egison is written in Haskell and being distributed as a Hackage package.


Developed and maintained on GitHub by the community. License is MIT.


Egison on Rosseta Code, Reddit.
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