Proposal: Add concatMapM function (#2042)

[Aaron Denney]

On 2008-01-31, Bulat Ziganshin <bulat.ziganshin at gmail.com> wrote:

[A bunch of quite sound advice]

> in FP language, the best way to provide encoding is to define it as
> pair of functions:
>
> data Encoding = Encoding { encode :: String -> String
>                          , decode :: String -> String }

Except these types are lies.

> data Encoding = Encoding { encode :: String -> Maybe [Word8]
>                          , decode :: [Word8] -> Maybe String }

-- 
Aaron Denney
-><-