Adding dup to Data.Tuple?

[Carter Schonwald]

dup is nice, but i dont really care what we call it as long as its not
annoying or dumbe :)

On Sun, Oct 28, 2018 at 6:22 PM Edward Kmett <ekmett at gmail.com> wrote:

> I have no strong preference for the name for 'jam', merely the existence
> of the dual construction if we're going to name one.
>
> However a needless name conflict with duplicate from Control.Comonad would
> be rather unfortunate.
>
> dup as the name for this operation has a ton of precedent in languages
> like forth, and its length is comparable to the already smashed fst and snd.
>
> -Edward
>
>
> On Sun, Oct 28, 2018 at 6:15 PM Oliver Charles <ollie at ocharles.org.uk>
> wrote:
>
>> jam? Seriously? I'm sure we can do much better wrt names than that.
>> Even dup I'd rather see expanded to "duplicate". The theory might have
>> shown that these are useful combinators, but that doesn't mean they
>> should decide the names.
>> On Sun, Oct 28, 2018 at 10:10 PM Edward Kmett <ekmett at gmail.com> wrote:
>> >
>> > If we're going to add this we should add the symmetric operation for
>> >
>> > jam :: Either a a -> a
>> >
>> > to Data.Either. (Name taken from Conal's compiling to categories code.)
>> >
>> > My own code has called these diag and codiag respectively. I happily
>> yield to a nicer convention.
>> >
>> > I have no real preference for whether we do the simple version in
>> Data.Tuple (which has a lot of precedent, as Data.Tuple tends to have lots
>> of little simple combinators that could be done more generally as arrows)
>> or moving it into Control.Arrow.
>> >
>> > -Edward
>> >
>> > On Sun, Oct 28, 2018 at 12:07 PM Ivan Perez <ivan.perez at keera.co.uk>
>> wrote:
>> >>
>> >> On 28/10/18 09:48, Vanessa McHale wrote:
>> >> > According to GHCi,
>> >> >
>> >> > λ:> import Control.Arrow
>> >> > λ:> :t (id &&& id)
>> >> > (id &&& id) :: b -> (b, b)
>> >> >
>> >> > That is, this implementation has type a -> (a, a) as well.
>> >> Yes, yes, that's what I meant by "it works for functions as well (since
>> >> they are arrows)"
>> >>
>> >> Ivan
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