abstactions and concrete implementations of mutable containers

 One of Haskell's strengths is immutable data structures. These structures make
 it easier to reason about code, simplify concurrency and parallelism, and in
 some cases can improve performance by allowing sharing. However, there are
 still classes of problems where mutable data structures can both be more
 convenient, and provide a performance boost. This library is meant to provide
 such structures in a performant, well tested way. It also provides a simple
 abstraction over such data structures via typeclasses.
 .
 This package provides a library for the Haskell programming language.
 See http://www.haskell.org/ for more information on Haskell.