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[Caml-list] Polymorphism and the "for" loop
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Date: -- (:)
From: Jon Harrop <jon@j...>
Subject: Re: [Caml-list] Polymorphism and the "for" loop
On Friday 22 October 2004 07:19, skaller wrote:
> ...I consider that a bug...

I'd have to go right ahead and disagree with you there. Surely a "procedure" 
returns no information, which can be achieved by returning the only value 
from a type representing a singleton set, i.e. _the_ value of the type unit.

>  type void = []

Why not "`void"?

I've been wondering about this recently: how do the compilers store types 
which contain "unit". For example, if we have a tree:

type 'a 'b tree = Leaf of 'a | Node of 'b * 'a 'b tree * 'a 'b tree

Does a "unit unit tree" take up less space than a "int int tree"?

The reason I'm asking is that it might be nice to generalise data structures 
as much as possible and then specialise them using "unit" arguments.

Cheers,
Jon.

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