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Lean 4 fork for HoTT-compatible kernel extensions (Path types, transport, HITs). Maintained against upstream leanprover/lean4.
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Tom Levy e42892cfb6
doc: fix comment about String.fromUTF8 replacing invalid chars (#10240) 
Hi, the doc of `String.fromUTF8` previously said invalid characters are
replaced with 'A'. But the parameter `h : validateUTF8 a` guarantees
there are no invalid characters, so that explanation doesn't make sense
to me. This PR deletes that explanation (and fixes some unrelated
typos).

I also have a patch that uses `h` to prove each of the characters is
valid, eliminating the need for a default character
([pr/chore-String-fromUTF8-prove-valid](27f1ff36b2)),
would you be interested in merging that?

<details>
<summary>Notes on invalid characters from unchecked C++</summary>
I don't know if this function may be called from unchecked C++ with
invalid characters. If it may, I'm not sure what would happen with my
patched function... I'm not familiar with Lean's safety model, but it
seems like a bad idea to have a Lean function that takes a proof of a
proposition but is expected to operate in a certain way even if the
proposition is false. I think the safe approach is to have two functions
-- one that takes a proof and is only called from Lean, and another that
doesn't take a proof and replaces invalid chars (for use from C++, not
sure whether it's useful from Lean); I'd prefer to go even further and
report an error instead of silently replacing invalid characters (I'm
not sure if there is any easy way to report errors/panic in Lean code
called from C++).
</details>
2025-09-23 10:19:20 +00:00
.github chore: CI: ensure cache reuse in update-stage0 (#10359) 2025-09-12 14:56:32 +00:00
doc doc: testing Lean while avoiding rebuilds for downstream projects (#10328) 2025-09-10 13:53:34 +00:00
images
releases_drafts
script chore: include lean-lang.org in release checklist (#10450) 2025-09-19 03:46:32 +00:00
src doc: fix comment about String.fromUTF8 replacing invalid chars (#10240) 2025-09-23 10:19:20 +00:00
stage0 chore: update stage0 2025-09-23 06:22:49 +00:00
tests fix: Use @[tactic_alt] for bv_decide, mvcgen and similar tactics (#10506) 2025-09-23 07:40:02 +00:00
.gitattributes fix: mark doc parser tests as eol=lf (#10344) 2025-09-11 11:19:01 +00:00
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lean.code-workspace feat: overhaul meta system (#10362) 2025-09-17 21:04:29 +00:00
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README.md doc: update URLs that are currently pointing to redirects (#10397) 2025-09-17 15:50:07 +00:00
RELEASES.md

README.md

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