Data.List.join

[Donald Bruce Stewart]

josef.svenningsson:
> 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:
> http://www.google.com/codesearch?q=file%3A%5C.hs+intersperse&btnG=Search+Code
> 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