33baaccb20
This includes the examples from issues #2961, #3219 and #5667 in our test suite, so that we know when (accidentially) fix them. In fact this closes #3219, which (judging from the nightlies) was fixed last week by #6901.
45 lines
1.4 KiB
Text
45 lines
1.4 KiB
Text
inductive Tree (α : Type u) : Nat → Type u
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| leaf : Tree α 0
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| branch :
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(val : α)
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→ (left : Tree α n)
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→ (right : Tree α m)
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→ Tree α (n+m+1)
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def popLast {α : Type u} (heap : Tree α (o+1)) : (α × Tree α o) :=
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match o, heap with
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| (n+m), .branch a (left : Tree α n) (right : Tree α m) =>
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if r : m = 0 then
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--remove left
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match n, left with
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| 0, _ => (a, (Eq.symm $ r.subst $ Nat.zero_add m : 0=0+m)▸Tree.leaf)
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| (l+1), left =>
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let (res, (newLeft : Tree α l)) := popLast left
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(res, (Nat.add_right_comm l m 1)▸Tree.branch a newLeft right)
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else
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--remove right
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match m, right with
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| (r+1), right =>
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let (res, (newRight : Tree α r)) := popLast right
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(res, Tree.branch a left newRight)
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def SomePredicate (_ : Tree α n) : Prop := True
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/--
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info: equations:
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theorem popLast.eq_1.{u} : ∀ {α : Type u} (n m : Nat) (a : α) (left : Tree α n) (right : Tree α m),
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popLast (Tree.branch a left right) =
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if r : m = 0 then
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match n, left with
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| 0, x => (a, ⋯ ▸ Tree.leaf)
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| l.succ, left =>
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match popLast left with
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| (res, newLeft) => (res, ⋯ ▸ Tree.branch a newLeft right)
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else
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match m, right, r with
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| r.succ, right, r_1 =>
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match popLast right with
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| (res, newRight) => (res, Tree.branch a left newRight)
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-/
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#guard_msgs in
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#print equations popLast
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