Donald Bruce Stewart dons at
Sat Oct 21 09:31:51 EDT 2006

> Hi,
> I'd like to propose to include the following function in Data.List:
> join :: [a] -> [[a]] -> [a]
> join x xs = concat (intersperse x xs)
> I find that every time I use intersperse I also concat the result. And
> it seems that I'm not alone:
> A clear majority of all the uses of intersperse also use concat on the
> result. I think it seems worthwhile to give a name to that idiom.

Oh, that's a nice trick for working out apis. Good idea!

> The name 'join' was taken from Data.ByteString, where a similar function 
> exists.

Seems reasonable.  Want to submit a darcs patch, and maybe a quickcheck
property or two?

-- Don

More information about the Libraries mailing list