Front-end representation of programs. See Program for the entire program; Constraint for constraints such as less than or equal, greater than, etc; and Linear for linear functions.

Each variable can have a lower or upper bound.

Constraints such as less than or equal, greater than or equal, between,...

Functions for evaluating linear functions constraints for a given assignment of variables.

Linear functions with constant coefficients on variables, and a constant addition.

An entire program.

Linear functions are classified as either int-valued or real-valued, so we define KZ and KR as data kinds to denote this in the type.