lean-ja / lean-ja/lean-by-example
Monad はなぜ宇宙多相なのか
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要調査
- Dominant language
- Lean
- Stars
- 188
- Forks
- 15
- Avg merge
- 9h 8m
- Merged PRs (30d)
- 6
Description
-- TODO: モナドは宇宙多相であってほしいので宇宙多相になっているようだ。
-- ReaderT と何が違う？？？
/-- info: Monad.{u, v} (m : Type u → Type v) : Type (max (u + 1) v) -/
#guard_msgs in #check Monad
返り値の宇宙レベルが引数の宇宙レベルと異なるような例を見たことがないが、そういうことをしたいこともあるのか？？
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 Lean snippet in the issue, especially #check Monad and the TODO comparing it with ReaderT. Investigate what the universe parameters mean and whether a differing result universe is useful; the work is done when the example documents that answer and clarifies the Monad/ReaderT distinction.
Written by the indexing model from the issue text.
Assessment
- Domain
- documentation
- Issue type
- Documentation
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 30/100