Lean 4 fork for HoTT-compatible kernel extensions (Path types, transport, HITs). Maintained against upstream leanprover/lean4.
2441bf1f76
This PR makes `simp` consult its own cache more often, to avoid replicating work. Before, the simp cache was checked upon entry of `simpImpl` only, which then calls `simpLoop`, which recursively iterates the `pre`-lemmas, without checking the cache again. Now, `simpLoop` itself checks the cache. This seems more principled, given that `simpLoop` is actually putting entries into the cache for each of its calls, so it’s more uniform if it checks the cache itself. This avoids repeated rewrites. For example given ``` theorem ab : a = b := testSorry theorem bc : b = c := testSorry example (h : P c) : P b ∧ P a := by simp [ab, bc, h] ``` simp would rewrite `b ==> c` twice (once as part of `b ==> c` and then again as part of `a ==> b ==> c`). And it’d be order dependent: With ``` example (h : P c) : P a ∧ P b := by simp [ab, bc, h] ``` the `a ==> b ==> c` chain would insert `b ==> c` into the cache, and picked up by `simpImpl` when rewriting `P b`. With this change, `b ==> c` is performed only once in both examples. Instruction counts on stdlib and mathlib both show a mild improvement across the board (0.5%), with individual modules improving by up to 4% in stdlib and even more in mathlib. (This does not check the cache before applying `post`, which explains where there are still some repeated rewrites in the trace logs. But I’m less sure about inserting a cache check here and so I am treading carefully here. It’s also going to be at most one `post` application that’s duplicated, because if `post` returns `.visit`, we go back to `pre` and thus a cache check.) |
||
|---|---|---|
| .github | ||
| doc | ||
| images | ||
| nix | ||
| releases_drafts | ||
| script | ||
| src | ||
| stage0 | ||
| tests | ||
| .gitattributes | ||
| .gitignore | ||
| .gitpod.Dockerfile | ||
| .gitpod.yml | ||
| .ignore | ||
| CMakeLists.txt | ||
| CMakePresets.json | ||
| CODEOWNERS | ||
| CONTRIBUTING.md | ||
| flake.lock | ||
| flake.nix | ||
| lean-toolchain | ||
| lean.code-workspace | ||
| LICENSE | ||
| LICENSES | ||
| README.md | ||
| RELEASES.md | ||
This is the repository for Lean 4.
About
- Quickstart
- Homepage
- Theorem Proving Tutorial
- Functional Programming in Lean
- Documentation Overview
- Language Reference
- Release notes starting at v4.0.0-m3
- Examples
- External Contribution Guidelines
Installation
See Setting Up Lean.
Contributing
Please read our Contribution Guidelines first.
Building from Source
See Building Lean.