From: Francois Thomasset <francois.thomasset@inria.fr>
To: Francois Rouaix <francois@rouaix.org>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] mystified by typing of optional arguments
Date: Thu, 03 Apr 2003 17:04:04 +0200 [thread overview]
Message-ID: <200304031504.h33F44Y23671@pelops.inria.fr> (raw)
In-Reply-To: Message from Francois Rouaix <francois@rouaix.org> of "Thu, 03 Apr 2003 16:50:44 +0200." <A5D19256-65E3-11D7-8811-000A95773ED2@rouaix.org>
> Hi all,
> The following example mystifies me
>
> let f ?opt x =
> match opt with
> | None -> x
> | Some dx -> x + dx
>
> let g x = x + 1
>
>
> let h1 = function
> | 0 -> [g]
> | _ -> [f; g]
>
>
> let h2 = function
> | _ -> [f; g]
>
>
> h1 is typable but not h2.
> Why is that ?
You cant' type [f;g] either !
# [ f ; g ];;
This expression has type int -> int but is here used with type
?opt:int -> int -> int
While [g;g] is a list of funs
FT
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next prev parent reply other threads:[~2003-04-03 15:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-03 14:50 Francois Rouaix
2003-04-03 15:04 ` Francois Thomasset [this message]
2003-04-03 15:05 ` Ville-Pertti Keinonen
2003-04-03 15:08 ` Eric C. Cooper
2003-04-03 15:13 ` Jacques Carette
2003-04-04 0:36 ` Jacques Garrigue
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