lean-ja / lean-ja/lean-by-example
`Fin` 型については値で match ができる
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データ型
項
- Dominant language
- Lean
- Stars
- 188
- Forks
- 15
- Avg merge
- 9h 8m
- Merged PRs (30d)
- 6
Description
def Fin.even (n : Fin 4) : Bool :=
match n with
| 0 => true
| 1 => false
| 2 => true
| 3 => false
#guard Fin.even 2
#guard ! Fin.even 3
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 Fin.even example and its two #guard checks in the issue. Determine where this example belongs in the book, then confirm that the documented value-pattern matching example and both checks are correct; the issue does not name a target file.
Written by the indexing model from the issue text.
Assessment
- Domain
- documentation
- Issue type
- Documentation
- Difficulty
- 1/5
- Estimated time
- Under an hour
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100