#### Topic: [Haskell] the Interpreter of mathematical expressions

Kind day, there Is a task to write the calculator on Haskell, yes not idle time, and what also some calculations could add in variables. In addition to it expressions register in reverse Polish notation. Actually, with the calculator of problems is not present - on any such miracle is written for 5 minutes. The problem arose in that as these results between calculations to save. What task candidate solutions are?