Questions: Checking for Understanding

We test whether a human has understood a story by asking questions, first to check on retention of explicitly stated facts, then for the ability to draw reasonable conclusions.

• We return attention to the John Alden story from whatever else we were doing, by explicitly making its context frame, ja-story, the current context.

    (tell '((:clear-slot *context* current)
            (current *context* ja-story))
          :comment "In the John Alden story ...")

• This question follows the access path from context, to speaker, to wife, to age. Her name is only retrieved for nicely presenting the output.

    (ask '((:the ?me (speaker (current *context*) ?me))
           (:the ?w (wife ?me ?w))
           (age ?w ?a ?units)
           (name ?w ?n))
         :collect '(?n is ?a ?units old)
         :comment "How old is my wife?")

  The :collect keyword provides restructured output.

  QUERYING:  How old is my wife?
  
   Input preds:          (:the ?me (speaker (current *context*) ?me)) 
                         (:the ?w (wife ?me ?w)) (age ?w ?a ?units) (name ?w ?n)
  
   Result:
     Bindings:            ?n     --- "priscilla"
                          ?units   --- years
                          ?a     --- 23
                          ?w     --- frame1-wife "priscilla"
                          ?me    --- frame1 "john alden"
                          ?$x20  --- ja-story
                         
    => (("Priscilla" IS 23 YEARS OLD))

• This question checks that obvious inferences were made from the given information, by retrieving Priscilla's husband and then his name.

    (ask '((husband Priscilla ?h)
           (:eval (pp-frame '?h))
           (name ?h ?n))
         :comment "Who is Priscilla's husband?"
         :collect '?n)

  The special :eval form applies the lisp function pp-frame to the frame bound to the variable ?h, to display it on the terminal. Then the name is returned.

  QUERYING:  Who is Priscilla's husband?
  
   Input preds:          (husband priscilla ?h) (:eval (pp-frame (quote ?h))) 
                         (name ?h ?n)
                         
  Frame1: 
    Isa:        things objects physical-objects people
    Name:       "john alden"
    Age:        (25 years)
    Wife:       frame1-wife
    Gender:     male
    Spouse:     frame1-wife
  
   Result:
     Bindings:            ?n     --- "john alden"
                          ?h     --- frame1 "john alden"
                         
    => ("John Alden")

• This question has more than one answer, so both are returned.

    (ask '((name (friend Priscilla) ?name))
         :comment "What is Priscilla's friend's name ?"
         :collect '?name)

  Here we collect two names into a list.

  QUERYING:  What is Priscilla's friend's name ?
  
   Input pred:           (name (friend priscilla) ?name)
  
   Result (1 of 2):
     Bindings:            ?name  --- "cotton mather"
                          ?$x21  --- |cotton mather|
                         
   Result (2 of 2):
     Bindings:            ?name  --- "miles standish"
                          ?$x21  --- |miles standish|
                         
    => ("Miles Standish" "Cotton Mather")