Re: [Caml-list] How to read three integers from a text-file... ?

[Dave Berry <daveb@tardis.ed.ac.uk>]

At 14:20 30/04/2002, Francois Pottier wrote:
>The function that concatenates CPS-encoded tuples is as follows:
>
>  let (++) tuple1 tuple2 k =
>    tuple2 (tuple1 k)
>
>A simple ``tuple'' that contains one integer (read from standard input
>when the tuple is queried) is
>
>  let int k =
>    k (int_of_string (input_line stdin))

Neat.  In practice you'd want to thread the input stream (or possibly the
input operation) through the combinators.

>You can then read, say, three integers from standard input and compute
>something out of them in the following way:
>
>  (int ++ int ++ int) (fun x y z -> x + y * z)

Perhaps it would be neat to have some syntactic sugar for this, e.g.:

	bind <pat> = <exp1>  in <exp2> end

as sugar for

	<exp1> (fun <pat> -> <exp2>)

(This is simply the opposite application order from the expansion of "let"
bindings:
	let <pat> = <exp1> in <exp2> end
 is sugar for
	(fun <pat> -> <exp2>) (<exp1>).
Of course, the types are different, and "let" bindings also generalise type
variables).

Dave.]


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