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Date: Fri, 29 Apr 2011 15:17:40 +0400
Message-ID: <BANLkTin1nQt3iDamEiycPOmoZT73gkHPAg@mail.gmail.com>
From: Dmitry Bely <dmitry.bely@gmail.com>
To: caml-list@inria.fr
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Subject: Re: [Caml-list] Comparing variant types

On Fri, Apr 29, 2011 at 2:54 PM, Andrew <newsgroups.fr@gmail.com> wrote:
>> type dir = Left | Right | Up | Down | No_op
>>
>> let dir_equal d1 d2 = match d1,d2 with
>> | (Left, Left)
>> | (Right,Right)
>> | (Up, Up)
>> | (Down,Down)
>> | (No_op,No_op)
>>  ->  true
>> | (Left,(Right|Up|Down|No_op))
>> | (Right,(Left|Up|Down|No_op))
>> | (Up,(Left|Right|Down|No_op))
>> | (Down,(Left|Right|Up|No_op))
>> | (No_op,(Down|Up|Right|Left))
>> ->  false
>
>
> Why not write directly
>        let dir_equal = fun d1 d2 ->
>          | Left Left
>          | Right Right
>          | Up Up
>          | Down Down
>          | No_op No_op ->  true
>          | _ -> false

"Directly" means "syntactically incorrect"? :) As for _ clause - you'd
better to avoid it.

- Dmitry Bely