Provides a simple way to expose Haskell functions to Mathematica via the MathLink interface. One defines a Haskell function of type ML () (a Monad built on top of IO ) and provides a pair of String s that function analogously to the :Pattern: and :Arguments: directives for Mathematica's mprep utility. Data can be marshaled either as an Expression or, more generally, as an instance of the Expressible class. The library does not use or require foreign export declarations, so may be used interactively.