Rename bound variable tactic
This files defines a tactic
rename_var whose main purpose is to teach
renaming of bound variables.
rename_var old newrenames all bound variables named
newin the goal.
rename_var old new at hdoes the same in hypothesis
example (P : ℕ → ℕ → Prop) (h : ∀ n, ∃ m, P n m) : ∀ l, ∃ m, P l m := begin rename_var n q at h, -- h is now ∀ (q : ℕ), ∃ (m : ℕ), P q m, rename_var m n, -- goal is now ∀ (l : ℕ), ∃ (n : ℕ), P k n, exact h -- Lean does not care about those bound variable names end