[thesz]

Author of the article discusses a library - two approaches of different (parts of) libraries.

It is quite possible you may need to have RAII somewhere in Haskell code and that's where things like parametrized monads are good: http://blog.sigfpe.com/2009/02/beyond-monads.html

It is a library and I keep saying that what is usually programming language feature is just a library in Haskell.