(object-contract member-spec )
Produces a contract for an object.
Each of the contracts for a method has the same semantics as the corresponding function contract, but the syntax of the method contract must be written directly in the body of the object-contract – much like the way that methods in class definitions use the same syntax as regular function definitions, but cannot be arbitrary procedures. The only exception is that ->d contracts implicitly bind this to the object itself.
A function contract that recognizes mixins. It guarantees that the input to the function is a class and the result of the function is a subclass of the input.
Produces a function contract that guarantees the input to the function is a class that implements/subclasses each type, and that the result of the function is a subclass of the input.
Accepts a class or interface and returns a flat contract that recognizes objects that instantiate the class/interface.
interface : interface?
Returns a flat contract that recognizes classes that implement interface.
class : class?
Returns a flat-contract that recognizes classes that are subclasses of class.