Metalevel Facilities and Database Architecture

Abstract

In section 14.3 we introduced dynamic binding — the run-time binding of execution code to a message. Static binding is not possible because the execution code for a message selector depends on the target object and the latter is only known at run-time. ‘Print’ messages are good examples of the need for dynamic binding: many objects provide a public method named ‘Print’ but each object may define them differently; thus the code to execute the message “Print(<target>, ...)” can only be determined once the class that <target> is an instance of is known.