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Module Lazy: deferred computations.
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<H2>17.12 Module <TT>Lazy</TT>: deferred computations.</H2><A NAME="s:Lazy"></A>
<A NAME="@manual336"></A><PRE>
type 'a status =
| Delayed of (unit -> 'a)
| Value of 'a
| Exception of exn
;;
type 'a t = 'a status ref;;
</PRE>
<BLOCKQUOTE>
A value of type <CODE>'a Lazy.t</CODE> is a deferred computation (also called a
suspension) that computes a result of type <CODE>'a</CODE>. The expression
<CODE>lazy (expr)</CODE> returns a suspension that computes <CODE>expr</CODE>.</BLOCKQUOTE>
<PRE>
val force: 'a t -> 'a;;
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<A NAME="@manual337"></A><BLOCKQUOTE>
<CODE>Lazy.force x</CODE> computes the suspension <CODE>x</CODE> and returns its result.
If the suspension was already computed, <CODE>Lazy.force x</CODE> returns the
same value again. If it raised an exception, the same exception is
raised again.</BLOCKQUOTE>
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