Expressions are written in Telerik Reporting scripting language. The language is based on mathematical expressions, and is case insensitive.
When you write an expression, you have access to many built-in fields, collections, and functions that you can use alone or combine with other terms. You can add function calls, operators, constants, fields, parameters, items from the built-in collections to an expression. Built-in function calls include aggregation, commonly used utility functions, and conversion methods. You can also add references to functions defined in your code (see user functions).