lean-ja / lean-ja/lean-by-example
明らかな場合はパターンマッチの枝が省略できるという例
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コード例
構文・パーサ
- Dominant language
- Lean
- Stars
- 188
- Forks
- 15
- Avg merge
- 9h 8m
- Merged PRs (30d)
- 6
Description
def NonemptyList (α : Type) := { xs : List α // xs.length > 0}
def head {α : Type} (xs : NonemptyList α) : α :=
match xs with
-- パターンマッチが省略できる（Lean が賢いから）
| ⟨x :: _xs, _⟩ => x
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 code example in the issue body. The payload names no target file or test, so first identify where this example belongs; done means incorporating the example in the appropriate documentation location and confirming it renders and explains the omitted pattern-matching branch.
Written by the indexing model from the issue text.
Assessment
- Domain
- documentation
- Issue type
- Documentation
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100