Expression types define the computational power of BRFplus. Each expression type defines a self-contained computational unit with a well-defined logic. Expressions use a context or nest other expressions to calculate, determine, or derive a result. An expression can be considered to be an instance of an expression type behaving according to the expression type's logic. An expression can be reused as a nested building block for a rule, starting with a function as its assigned top expression.

BRFplus comes with a set of common expression types and is regularly enhanced by new expression types. You can create your own expression types and use it in rules.

The predefined types of expression are: