signature MLTON_CONT =
   sig
      type 'a t
      val callcc: ('a t -> 'a) -> 'a
      val isolate: ('a -> unit) -> 'a t
      val prepend: 'a t * ('b -> 'a) -> 'b t
      val throw: 'a t * 'a -> 'b
      val throw': 'a t * (unit -> 'a) -> 'b
   end- 
type 'a tthe type of continuations that expect a value of type 'a.
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callcc fapplies fto the current continuation. This copies the entire stack; hence,callcctakes time proportional to the size of the current stack.
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isolate fcreates a continuation that evaluates fin an empty context. This is a constant time operation, and yields a constant size stack.
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prepend (k, f)composes a function fwith a continuationkto create a continuation that first doesfand then doesk. This is a constant time operation.
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throw (k, v)throws value vto continuationk. This copies the entire stack ofk; hence,throwtakes time proportional to the size of this stack.
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throw' (k, th)a generalization of throw that evaluates th ()in the context ofk. Thus, for example, ifth ()raises an exception or captures another continuation, it will seek, not the current continuation.