22 lines
524 B
Text
22 lines
524 B
Text
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partial def reverse {α} (as : List α) : List α :=
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let rec loop : List α → List α → List α
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| [], r => r
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| a::as, r => loop as (a::r)
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loop as []
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#eval reverse [3, 2, 1]
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#eval reverse [1, 2, 3, 4]
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#print reverse
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#print reverse.loop
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#print reverse.loop._unsafe_rec
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partial def appendRev {α} (extra : List α) (as : List α) : List α :=
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let rec loop (as acc : List α) : List α :=
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match as, acc with
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| [], r => extra ++ r
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| a::as, r => loop as (a::r)
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loop as []
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#eval appendRev [3, 4] [1, 2, 0]
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