deftactic Macro

Summary

Defines a tactic function for use in context strategies.

Package

kw

Signature

deftactic tactic-name type lambda-list &body body => tactic-name

Arguments

tactic-name⇩	A symbol.
type⇩	Either :static or :dynamic.
lambda-list⇩	A two argument lambda list.
body⇩	A function body.

Values

tactic-name

A symbol.

Description

The macro deftactic defines a new conflict resolution tactic named tactic-name.

type is the type of the tactic, which may be :static if body does not look into the slots of the objects making up the instantiation, otherwise :dynamic.

lambda-list specifies two variable, which will be bound to two instantiation objects and when the forms of body are evaluated. body should return non-nil if and only if the first instantiation object is preferred to the second.

deftactic also defines a function named tactic-name and body can be preceded by a documentation string.

The newly defined tactic may be used as any in-built tactic.

Examples

(deftactic prefer-trucks :static (inst1 inst2)
  (flet ((truck-p (obj) (typep obj 'truck)))
    (and (some #'truck-p (inst-token inst1))
      (notany #'truck-p (inst-token inst2)))))

The new tactic may be used in a defcontext form:

(defcontext my-context :strategy (prefer-trucks))

See also

inst-bindings
inst-token
inst-rulename
defcontext