Re: Adding dup to Data.Tuple?

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 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 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

On 28/10/18 09:48, Vanessa McHale wrote: they are arrows)"

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