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36 lines
751 B
Plaintext
36 lines
751 B
Plaintext
List.fold
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: ∀(T: *)
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∀(list: (List T))
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(List.Folder T)
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= λT λlist
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λP λcons λnil
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let fold_P = λxs(P)
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let fold_cons = λhead λtail (cons head ((List.fold T tail) P cons nil))
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let fold_nil = nil
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(~list fold_P fold_cons fold_nil)
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// old version:
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//List.fold
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//: ∀(T: *)
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//∀(list: (List T))
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//(List.Folder T)
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//= λT λlist
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//λP λcons λnil
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//(~list λxs(P)
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//λhead λtail (cons head ((List.fold T tail) P cons nil))
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//nil)
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// non-fusible version:
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//List.fold
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//: ∀(T: *)
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//∀(list: (List T))
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//(List.Folder T)
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//= λT λlist
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//let P = λxs(List.Folder T)
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//let cons = λhead λtail (List.Folder.cons T head (List.fold T tail))
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//let nil = (List.Folder.nil T)
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//(~list P cons nil)
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