data (,) a b = (,) a b -- Defined in GHC.Tuple

instance (Bounded a, Bounded b) => Bounded (a, b)

-- Defined in GHC.Enum

instance (Eq a, Eq b) => Eq (a, b) -- Defined in Data.Tuple

instance (Ord a, Ord b) => Ord (a, b) -- Defined in Data.Tuple

instance (Read a, Read b) => Read (a, b) -- Defined in GHC.Read

instance (Show a, Show b) => Show (a, b) -- Defined in GHC.Show

On Sat, Jul 11, 2009 at 12:25 PM, Patrick LeBoutillier <patrick.leboutillier@gmail.com> wrote:

On Sat, Jul 11, 2009 at 1:13 PM, Chaddaï Fouché<chaddai.fouche@gmail.com> wrote:
> On Sat, Jul 11, 2009 at 5:57 PM, Patrick
> LeBoutillier<patrick.leboutillier@gmail.com> wrote:
>>> Does this make sense?
>>
>> Yes, perfectly. I guess you just have to know about it... :)
>>
>
> Well, it's the lexicographic order, the most "natural", in any case
> the most used order for tuples, so it would be strange to have other
> expectations by default
>
> Of course, the mechanism by which this work is interesting by itself.

Really interesting in fact. It shows how generic these concepts really
are. But it wasn't obvious to me that a pair could be an instance of
Ord.

This kind of gives you a clue:

Prelude> :info ()
data () = () -- Defined in GHC.Unit
instance Bounded () -- Defined in GHC.Enum
instance Enum () -- Defined in GHC.Enum
instance Eq () -- Defined in Data.Tuple
instance Ord () -- Defined in Data.Tuple
instance Read () -- Defined in GHC.Read
instance Show () -- Defined in GHC.Show

but is there a way to do the equivalent of:

Prelude> :info (a,b)
or
Prelude> :info (Int,String)

?

Patrick

>
> --
> Jedaï

>

--
=====================
Patrick LeBoutillier
Rosemère, Québec, Canada
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