lean-ja / lean-ja/lean-by-example

`unfold_projs` タクティクを紹介する

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コード例 タクティク 型クラス 準備完了
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Lean
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Merged PRs (30d)
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Description

Zulip: low level tactics

import Mathlib.Tactic

example {α : Type} (l : List α) : [] ++ l = l := by
  -- Append 型クラスを展開して `++` という記法の実際の実装を取り出す
  unfold_projs
  guard_target =ₛ [].append l = l

  dsimp

example {α β : Type} (f : α → β) (a₁ a₂ a₃ : α) : f <$> [a₁, a₂, a₃] = [f a₁, f a₂, f a₃] := by
  -- Functor 型クラスを展開して `<$>` という記法の実装を取り出す
  unfold_projs
  guard_target =ₛ List.map f [a₁, a₂, a₃] = [f a₁, f a₂, f a₃]

  dsimp

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the unfold_projs examples in the issue and verify them with import Mathlib.Tactic. Add the Japanese introduction in the repository's existing example documentation structure, preserving the two examples and their explanations as the completion criteria.

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
Mostly clear
Newbie friendliness
45/100

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