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[Caml-list] variant with tuple arg in pattern match?
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Date: -- (:)
From: Alain Frisch <frisch@c...>
Subject: Re: [Caml-list] variant with tuple arg in pattern match?
On Sun, 8 Apr 2001, Pierre Weis wrote:
> I suggest to explicitely annotate the constructor definitions as in:
> 
> type t =
> | C : int -> int -> t
> This notation is explicit, intuitive, and allows refined type checking
> in some cases (for instance
> type 'a t = C : int -> bool -> (int * bool) t).

How does this interact with pattern matching ?  If constructor types
are not uniform, it seems that it is no longer possible to 
say whether a simple (without guards) pattern matching is exhaustive or
not.

For instance, with the declaration:
  type 'a t = A : int t | B : 'a -> 'a t
do you issue a warning for:
  function B x -> x
?


-- 
  Alain Frisch

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