From: "Till Crueger" <Till.Crueger@gmx.net>
To: caml-list@yquem.inria.fr
Subject: How to add () to function parameters
Date: Wed, 14 Oct 2009 12:44:17 +0200 [thread overview]
Message-ID: <op.u1sdf3sfsoui26@mail.gmx.net> (raw)
Hi,
I am looking for a way to add a unit parameter to a function that takes an
arbitrary number of parameters. If the number of parameters is known this
is fairly easy and I can just do:
let lift1 f a =
fun () ->
f a;;
let lift2 f a b =
fun () ->
f a b;;
(all these create one closure per lifting)
etc...
However it is a bit of a hassle to have to code each of these lifts... So
what I am looking for is a way to extend this pattern to all numbers. So
far I got to the point that I can do the following:
let lift_once f a =
fun () ->
f a;;
let lift_more f a =
fun () ->
f () a;;
So for a function f taking two parameters a and b I can do
lift_more (lift_once f a) b
(two closures created)
and for a function taking the parameters a, b and c I can do
lift_more (lift_more (lift_once f a) b) c
(three closures created)
to get the lifted functions.
However this solution gets quite ugly with all the parentheses. Also there
are a lot of closures being produced and evaluated for any single lifting.
I had a look at the Jane Street blog post about variable argument
functions (http://ocaml.janestcapital.com/?q=node/22), which seems to do
similar things. However I have never been really good with CPS, so I don't
know if those techniques can be applied to this problem.
Is there any way to do this, which does not get this ugly. Also the
resulting lifted function should not contain too many closures.
Thanks for your help,
Till
next reply other threads:[~2009-10-14 10:40 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-14 10:44 Till Crueger [this message]
2009-10-16 15:15 ` [Caml-list] " Till Varoquaux
2009-10-16 15:22 ` Till Varoquaux
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