Hi Vlatko.

On 2 July 2013 16:03, Vlatko Basic <vlatko.basic@gmail.com> wrote:
Is there a nicer way to extract the 'IO String' from 'IOS',
without 'case' or without pattern matching the whole 'P'?

You might enjoy the newtype package.

http://hackage.haskell.org/package/newtype 

Hope this helps,
Ozgur.