42e98bd3c9
This PR changes the signature of `Array.swap`, so it takes `Nat` arguments with tactic provided bounds checking. It also renames `Array.swap!` to `Array.swapIfInBounds`.
12 lines
370 B
Text
12 lines
370 B
Text
def myfunUnsafe (x : Array α) (i : Fin x.size) : Array α :=
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sorry
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@[implemented_by myfunUnsafe]
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def myfun (x : Array α) (i : Fin x.size) : Array α :=
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let next := 2*i.1 + 1
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if h : next < x.size then
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have : x.size - next < x.size - i.1 := sorry
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myfun (x.swap i next) ⟨next, (x.size_swap _ _).symm ▸ h⟩
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else
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x
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termination_by x.size - i.1
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