The call type(expr, `<`) checks if expr is of type , that is, if it is a strict inequality. It returns true if expr is of type `<`, and false otherwise.

The call type(expr, `<=`) checks if expr is of type `<=`, that is, if it is an inequality. It returns true if expr is of type `<=`, and false otherwise.

Both types `<` and `<=` are surface type checks, and are therefore very fast. The supertypes relation and boolean include both kinds of inequality.