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[Caml-list] operators: compose and Haskell's $ operator
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Date: -- (:)
From: Brian Rogoff <bpr@b...>
Subject: Re: [Caml-list] operators: compose and Haskell's $ operator
On Wed, 25 Apr 2001, Charles Martin wrote:
> Does someone out there have an out-of-the box solution for adding
> composition and an equivalent for Haskell's $ operator to OCaml?
> 
> I've been using let (<<) f g x = f (g x) for composition, but an

You should be warned that that doesn't mix nicely with CamlP4's quotation 
syntax.

>equivalent for the $ operator eludes me, as it needs to be right
>associative and of low precedence.

Maybe <->? Let's test it

# let ( <-> ) f x = f x;;
val ( <-> ) : ('a -> 'b) -> 'a -> 'b = <fun>
# (fun x -> x + 1) <-> (5 / 2) + 3;;
- : int = 6
# (fun x -> x + 1) <-> (5 / 2) * 3;;
- : int = 7

> Maybe someone with some Haskell envy has figured something out using
> camlp4?

I admit I have a little Haskell envy (type classes and the `infix` syntax :), 
but I can probably live with some parentheses ...

-- Brian


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