Language Reference/Built-in entities

Visual Prolog contains an embedded hidden class, which provides declarations and implementations to all built-in constants, domains, and predicates.

These built-in constants, domains, and predicates can be used both during compilation (for example, in #if ... constructions) and in implementations (which are supported for runtime).

Each compilation unit implicitly contains the declaration of this embedded hidden class. To disambiguate from other entities with the same name you can use "::" before names of built-in items.

Notice that the clause variable This is automatically defined in the clauses for object predicates.