Re: [Caml-list] How do I define prog1?

[Maxence Guesdon <max@sbuilders.com>]

Mattias Waldau a écrit :
> 
> I would like to define a (prog1 a b) which first evaluates a, then b, and
> returns the
> value of a. (Would be nice if I could have arbitrary number of args.)
> 
> I defined it as
> 
> let prog1 a b = a
> 
> Works well in compiled code, first evaluates a, then b.
> However bytecode first evaluates b, then a.
> 
> In this cases, call-by-name would be very nice.
> 
> One obvious solution is to write
> 
> let temp = a in
> b;
> temp
> 
> but that is much too clumsy.
> 
> /mattias
> 
> -------------------
If you want prog1 to evaluate a then b, you can do

let prog1 fa fb =
	let a = fa () in
	let _ = fb() in
	a
then call prog1 this way :

prog1 (fun () -> a) (fun () -> b);

--
Maxence
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