All Manuals > KnowledgeWorks and Prolog User Guide > 7 Reference Guide

NextPrevUpTopContentsIndex

not

Backward Chaining Goal
Summary

A goal that is satisfied when another goal fails.

Signature

not {condition}*

Arguments

condition

Any backward chaining goal.

Description

If not is used in a backward chaining goal, it succeeds if the condition contained within it fails. In this usage, only one condition is allowed.

If not is used in a forward chaining pre-condition, it succeeds if any of the condition contained within it fail. In this usage, the conditions may only contain expressions normally allowed in forward chaining pre-conditions (object base references and lisp tests).

Examples
(not (truck ?truck driver ?driver) (test ?driver))
See also

test


KnowledgeWorks and Prolog User Guide (Unix version) - 26 Feb 2015

NextPrevUpTopContentsIndex