Control-Monad-ST2

A variation on the ST monad with two type parameters.

https://github.com/kevinbackhouse/Control-Monad-ST2

Latest on Hackage:

0.1.0.1

This package is not currently in any snapshots. If you're interested in using it, we recommend adding it to Stackage Nightly. Doing so will make builds more reliable, and allow stackage.org to host generated Haddocks.

BSD-3-Clause licensed by Kevin Backhouse

Maintained by [email protected]

The ST2 monad is like the ST monad, but with finer-grained control over access to mutable state. The phantom type parameters r and w are used to track the read and write dependencies of the computation. If a computation of type ST2 r w a is polymorphic in w then it does not write any external state. If it is also polymorphic in r then it does not read any external state.