[Haskell-cafe] What is a number. (Was: Num instances for 2-dimensional types)

Lennart Augustsson lennart at augustsson.net
Mon Oct 5 13:06:27 EDT 2009


OK, "just pairs" have no arithmetic, but one way of defining
arithmetic is to treat the pairs as complex numbers.  Or as mantissa
and exponent.  Or as something else.  So there's nothing wrong, IMO,
to make pairs an instance of Num if you so desire.  (Though I'd
probably introduce a new type.)

On Mon, Oct 5, 2009 at 6:46 PM, Miguel Mitrofanov <miguelimo38 at yandex.ru> wrote:
>> "Just pairs" have no natural arithmetic upon them.
>
> Exactly my point.
>
>> BTW. the missing term of M.M. is DUAL NUMBERS.
>
> Remembered this already. Thanks anyway.
>
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