From: Gabriel Kerneis <kerneis@pps.jussieu.fr>
To: Jeff Meister <nanaki@gmail.com>
Cc: Ashish Agarwal <agarwal1975@gmail.com>, Caml List <caml-list@inria.fr>
Subject: Re: [Caml-list] use identity for default function
Date: Thu, 7 Feb 2013 21:06:19 +0100 [thread overview]
Message-ID: <20130207200619.GA28009@kerneis.info> (raw)
In-Reply-To: <CAHaHOqRgRkreoKpzs8BG-OSa+g3WQaR_kAAHcYf24QCTbH=vzQ@mail.gmail.com>
On Thu, Feb 07, 2013 at 11:53:25AM -0800, Jeff Meister wrote:
> Can't you simply define it this way?
> # external id : 'a -> 'b = "%identity";;
> # let foo ?(f = id) x = f x;;
If using unsafe features is okay, you might do even shorter:
# let foo ?(f = Obj.magic) x = f x ;;
val foo : ?f:('a -> 'b) -> 'a -> 'b = <fun>
But remember that “Obj.magic is not part of the language”!
For some good reason:
# let x : int list = foo 0;;
val x : int list = []
--
Gabriel
next prev parent reply other threads:[~2013-02-07 20:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-07 19:22 Ashish Agarwal
2013-02-07 19:53 ` Jeff Meister
2013-02-07 20:04 ` AW: " Gerd Stolpmann
2013-02-07 20:06 ` Gabriel Kerneis [this message]
2013-02-09 13:13 ` Goswin von Brederlow
2013-02-09 20:10 ` Jeff Meister
2013-02-07 19:59 ` Martin Jambon
2013-02-07 20:12 ` Gabriel Kerneis
2013-02-07 20:57 ` Ashish Agarwal
2013-02-08 2:47 ` Jacques Garrigue
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