Lean 4 fork for HoTT-compatible kernel extensions (Path types, transport, HITs). Maintained against upstream leanprover/lean4.
dca8d6d188
This PR enforces rules around arithmetic of `String.Pos.Raw`.
Specifically, it adopts the following conventions:
- Byte indices ("ordinals") in strings should be represented using
`String.Pos.Raw`
- Amounts of bytes ("cardinals") in strings should be represented using
`Nat`.
For example, `String.Slice.utf8ByteSize` now returns `Nat` instead of
`String.Pos.Raw`, and there is a new function `String.Slice.rawEndPos`.
Finally, the `HAdd` and `HSub` instances for `String.Pos.Raw` are
reorganized. This is a **breaking change**.
The `HAdd/HSub String.Pos.Raw String.Pos.Raw String.Pos.Raw` instances
have been removed. For the use case of tracking positions relative to
some other position, we instead provide `offsetBy` and `unoffsetBy`
functions. For the use case of advancing/unadvancing a position by an
arbitrary number of bytes, we instead provide `increaseBy` and
`decreaseBy` functions. For
offsetting/unoffsetting/advancing/unadvancing a position `p` by the size
of a string `s` (resp. character `c`), use `s + p`/`p - s`/`p + s`/`p -
s` (resp. `c + p`/`p - c`/`p + c`/`p - c`).
|
||
|---|---|---|
| .github | ||
| doc | ||
| images | ||
| 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 Install Lean.
Contributing
Please read our Contribution Guidelines first.
Building from Source
See Building Lean.