The following set of basic and special purpose predicates are supported:
| Predicate | Arguments |
|---|---|
| is/2 | ?Number, +Expr |
| >/2 | +Expr1, +Expr2 |
| </2 | +Expr1, +Expr2 |
| =</2 | +Expr1, +Expr2 |
| >=/2 | +Expr1, +Expr2 |
| =\=/2 | +Expr1, +Expr2 |
| =:=/2 | +Expr1, +Expr2 |
| between/3 | +Low, +High, ?Value |