Expandable formula parser as a Delphi (3-6) component. Can handle variables. When the parser needs the value of a variable, it creates an event to get it. Very fast if using the same formula with different values for variables, because it works in two steps: parsing to a tree structure and calculate. Different priorities for operators. Unary (exampe: sin) and binary (example: +) operators. List of operators is easy expandable to custom problem. Demo application. Source code on purchase.