[Haskell] evaluate function as a string

Hello! I am new to Haskell. I want to develop an application in which the user enters a mathematical equation, presumably as a string (any arbitrary equation, using any of the standard mathematical operators : +,*,^, etc, and any of the standard functions: sin, exp, etc.). I need to take that string, convert it to a real function, and evaluate it. Thank you. ______________________________________________________________________ Correo Yahoo! - 6MB, más protección contra el spam ¡Gratis! http://correo.yahoo.es