not Backward Chaining Goal

Summary

A goal that is satisfied when another goal fails.

Package

kw

Signature

not {condition}*

Arguments

Description

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

If not is used in a forward chaining pre-condition, it succeeds if any condition contained within it fail. In this usage, each condition may only contain expressions normally allowed in forward chaining pre-conditions (object base references and lisp tests). See 3.1.2 Forward Chaining Syntax for more details.

Examples

(not (truck ?truck driver ?driver) (test ?driver))

See also

test