18 lines
494 B
OCaml
18 lines
494 B
OCaml
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(* Purely functional queues *)
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type 'a t
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val empty : 'a t
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val enq : 'a -> 'a t -> 'a t
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val deq : 'a t -> ('a t * 'a) option
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val is_empty : 'a t -> bool
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(* The call [peek q] is [None] if the queue [q] is empty, and,
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otherwise, is a pair made of a queue and the next item in it to be
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dequeued. The returned queue contains the same items as [q], in the
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same order, but more efficient, in general, to use in further
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calls. *)
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val peek : 'a t -> ('a t * 'a) option
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