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From: oleg@pobox.com
To: caml-list@inria.fr
Subject: Re: Simple idea for making a function infix
Date: Mon, 13 Nov 2006 20:29:39 -0800 (PST)	[thread overview]
Message-ID: <20061114042939.BD07FAC04@Adric.metnet.fnmoc.navy.mil> (raw)


Haskell's back-quote notation has a notable limitation as it applies
to identifiers only. That is, we gain infix identifiers rather than
infix expressions. As it turns out, we can obtain infix expressions
without any change of syntax or any backticks:

  http://www.haskell.org/pipermail/haskell-prime/2006-March/000935.html
  http://www.haskell.org/haskellwiki/Infix_expressions

It seems that the second solution of the above page is similar to the
one just proposed for OCaml. For ease of comparison, in Haskell, ($) is
defined as [x $ y = x y] and flip flips the order of the arguments.

The first solution on that page can be rendered in Ocaml as follows:

	let (>--) x y = (x,y);;
	let (<--) (x,f) y = f x y;;

Now we can write

	# 3 >-- min <-- 4;;
	- : int = 3

We gain not only infix identifiers but infix expressions as well:

	let a = Array.make 3 'a';;
	val a : char array = [|'a'; 'a'; 'a'|]
	1 >-- Array.set a <-- 'b'; a;;
	- : char array = [|'a'; 'b'; 'a'|]

so we can use even three-argument functions as sort of `infix'...



             reply	other threads:[~2006-11-14  4:30 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-14  4:29 oleg [this message]
  -- strict thread matches above, loose matches on Subject: below --
2006-11-13  7:23 Keisuke Nakano

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