Math::Expr Parses mathematical expressions into a tree structure. The expressions may contain integers, real numbers, alphanumeric variable names, alphanumeric function names and most other characters might be used as operators. The operators can consist of multiple characters. The only limitation is that a variable or function name may not start on a digit, and not all chars are accepted in operation names. See the pod documentation of Math::Expr and Math::Expr::Opp for more info. Hakan Ardo