Data.List.join

Josef Svenningsson josef.svenningsson at gmail.com
Sat Oct 21 09:29:57 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:
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.

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

All the best,

Josef Svenningsson


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