leanprover-community / leanprover-community/lean
implement `apply f at h` as `replace h := f h`
Open
Nobody has claimed this yet.
enhancement
good first issue
- Dominant language
- C++
- Stars
- 434
- Forks
- 79
- PR merge metrics
- No merged PRs in 30d
Description
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the linked Zulip discussion, then locate the existing apply tactic entry point in the Lean repository. Done means the syntax apply f at h behaves like replace h := f h.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- compilers
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100