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11.1.3 Predicate Annotation

This section describes the annotations of predicates and how they are indicated in the reference pages for predicates of each given annotation. The annotations appear to the right of the title of the reference page.


The behavior of the predicate can be customized/redefined by defining one or more hooks. The mode and type annotations of a hookable predicate might not be absolute, since hooks added by the user can change the behavior.


The predicate is user defined, and is called by a hookable builtin. Typically, it is undefined initially, belongs to the user module, and if defined by the user, it is best defined as multifile, so that new clauses can be added by different software modules. For a hook, the mode and type annotations should be seen as guidelines to the user who wants to add his own hook; they describe how the predicate is used by the system.


You cannot call these directly but they can appear in files as ‘:- declaration’ and give information to the compiler. The goal template is preceded by ‘:-’ in the Synopsis.


A predicate that is defined in the development system only, i.e. not in runtime systems.


A predicate that is part of the ISO Prolog Standard.


A predicate that is not recommended in new code and that could be withdrawn in a future release.

Meta-predicates and operators are recognizable by the implicit conventions described below.

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