:BOUNDP

Purpose

Checks whether a variable has a binding.

  ((:BIND ?x 1)
   (:BOUNDP ?x)
   (:PRINTLN "?x is bound"))

  ((:FAIL (:BOUNDP ?y))
   (:PRINTLN "?y is not bound"))

Succeeds if the given variable is bound.

Fails if the variable is bound.

None.