lean4-htt/tests/lean/run/do_match_else.lean
2016-07-29 13:03:23 -07:00

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Text

open tactic
set_option pp.all true
definition app2 (f a b : expr) :=
expr.app (expr.app f a) b
example (a b c x y : nat) (H : nat.add (nat.add x y) y = 0) : true :=
by do
a ← get_local `a, b ← get_local `b, c ← get_local `c,
H ← get_local `H >>= infer_type,
(lhs, rhs) ← match_eq H,
nat_add : expr ← mk_const `nat.add,
p : pattern ← mk_pattern [] [a, b] (app2 nat_add a b) [app2 nat_add b a, a, b],
trace (pattern.output p),
[v₁, v₂, v₃] ← match_pattern p lhs | failed,
trace v₁, trace v₂, trace v₃,
constructor