I built the RealWorld app in Lean 4

(leangineer.com)

18 points | by saviorand 3 days ago ago

3 comments

  • solomonb an hour ago

    The secret of Lean4 is that its actually a great programming language, sort like a super Haskell. In fact I like it more as a programming language then as a proof checker!

    Dependent types are awesome for regular programming in addition to formal verification. For proof checking I actually prefer Agda.

  • saviorand 3 days ago

    I wanted to know if Lean 4 is usable for an everyday web app yet, not just for proofs, so I built RealWorld (the Medium clone) in it, frontend included, using Datastar. Looks like it's feasible now with the new libraries. This post describes the experience