;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;<pre><xmp>

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; ACT-R model of multicolumn addition
;;; using a visual-object representation,
;;; but not using the visual interface to 
;;; construct the representation from the display.
;;;
;;; Works with ACT-R 4.0 (2/6/97 or newer)
;;;
;;; This file contains an ACT-R model that
;;; can perform addition of two numbers.
;;; 
;;; A simple function call and a WWW interface
;;; are included.
;;;
;;; To have the model add 2 numbers, call
;;; the function actr-add with the numbers to be
;;; added: (actr-add 123 789).
;;;
;;;
;;; To use the WWW interface, you need to run
;;; the ACT-R on the Web application (follow the
;;; instructions provided with it), or use a
;;; web browser to connect to a site that has
;;; the model installed.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; This section contains the code to create the
;;; representation of a problem, present the interface,
;;; and display the results.  The ACT-R
;;; model is located farther down.


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; Global variables

;; these are used to create the visual-objects from the input numbers

(defparameter *addition-order* '(ones tens hundreds thousands ten-thousands hundred-thousands))
(defparameter *addition-number-names* '(zero one two three four five six seven eight nine))

(defvar *addition-answer*)   ; used to store the 'key-presses' made by the model

;; the rest are the parameters set in the interfaces
(defvar *number1*)
(defvar *number2*)
(defvar *v* nil)

(defparameter *addition-description*
"ACT-R model of multicolumn addition.")


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; This section contains the interface for the WWW using the
;;; ACT-R on the Web application by Elmar Schwarz

(defvar *WWW-interface*)
(setf *WWW-interface*
      '((:heading "Addition Model" 2)
        (:table)
        (:table)
        "Addend 1" (:string :sy *number1* 12345) (:new-row)
        "Addend 2" (:string :sy *number2* 67890) 
        (:table-end)
        (:table)
        (:checkbox "Trace" :sy *v* nil) 
        (:table-end)
        (:table-end)

        (:new-para)

        (:button "Run Model" )
        (:button "Production Rules" )
        (:button "Chunk types" )
        (:button "Chunks" )
        
        (:new-para)

         "TIME and SIZE:"
        (:new-para)
        "- It usually takes less than 1 minute for 1 run of the model"
        (:new-line)
        "- The trace of 1 run is approximatly 5k (3 pages) in size"))
        


(defun run-model (button-name)
	(cond ((string-equal button-name "Run Model" (if (and (numberp *number1*) (numberp *number2*))
                                  (actr-add-numbers)
                                  (format *standard-output* \"Both addents must be numbers~%\"))))
	((string-equal button-name "Production Rules") (let ((prods (no-output (pp))))
                                         (dolist (x prods)
                                           (pp-fct (list x))
                                           (spp-fct (list x))
                                           (format *standard-output* "~%"))))
	((string-equal "Chunk types" (wm)))
	((string-equal "Chunks" (dm)))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; This section contains the code to create the visual objects,
;;; and call the model.

;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; actr-add takes 2 numbers, and then calls the function which
;;; creates the visual objects for those numbers, and runs the
;;; model to add them.  The numbers must have the same number of
;;; digits, and be 5 or fewer digits long.

(defun actr-add (num1 num2)
  (setf *number1* num1)
  (setf *number2* num2)
  (actr-add-numbers))

;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; actr-add-numbers is called to set up the visual objects, add a goal to working memory, 
;;; focus on the goal, and then call run to start the model.
;;; The numbers that will be added are those in the global variables *number1* and *number2*.
;;; The 2 numbers that are to be added by the model must be the same length, and no more
;;; than 5 digits long. 


(defun actr-add-numbers ()
 
  (reset)
  (sgp-fct (list :v *v*))
 
  (let ((numstr1 (format nil "~a" *number1*))
        (numstr2 (format nil "~a" *number2*)))
    
    (if (and (< (length numstr1) 6) (= (length numstr1) (length numstr2)))
      (progn
    
        (format *standard-output* "Solving Problem:~%~%  ~S~%+ ~S~%" *number1* *number2*)

        (dotimes (i (+ 2 (length numstr1)))
          (format *standard-output* "-"))

        ;; clear the answer, and remove all visual objects from working memory
        
        (setf *addition-answer* nil)
        (deletewm-fct (no-output (swm isa visual-object)))
        
        ;; add the visual objects for the numbers to working memory
        
        (dotimes (i (length numstr1))
          (let ((val1 (mod *number1* 10))
                (val2 (mod *number2* 10)))
            (setf *number1* (truncate (/ *number1* 10)))
            (setf *number2* (truncate (/ *number2* 10)))
            
            (addwm-fct (list (list (gensym "vo") 'isa 'visual-object 
                                   'column (nth i *addition-order*) 'row 'top
                                   'value (nth val1 *addition-number-names*))))
            
            (addwm-fct (list (list (gensym "vo") 'isa 'visual-object 
                                   'column (nth i *addition-order*) 'row 'bottom
                                   'value (nth val2 *addition-number-names*))))))
        
        ;; add the + visual object to working memory
        
        (addwm-fct (list (list (gensym "vo") 'isa 'visual-object 
                               'column (nth (length numstr1) *addition-order*) 'row 'bottom
                               'value '+)))
        
        ;; set the goal, and call the model
        
        (modwme goal column nil carry nil)
        (WMFocus goal)
        (run)
        
        ;; output the answer 'typed' by the model
        
        (when *v* 
          (format *standard-output* "~%Solution:~%~%  ~a~%+ ~a~%"  numstr1 numstr2)

          (dotimes (i (+ 2 (length numstr1)))
            (format *standard-output* "-")))
        
        (format *standard-output* (if (= (length *addition-answer*) (length numstr1)) "~%  " "~% "))

        (dolist (key *addition-answer*)
          (format *standard-output* "~S" key))
        (format *standard-output* "~%"))

      ;; if the input is not valid, inform the user 
      (format *standard-output* "Must use equal length numbers of 5 or fewer digits for the addends."))))


;;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; store-key-press takes one parameter, which should be the number
;;; 'pressed' by the model.  The number is stored so the answer can be reported
;;; when the model finishes

(defun store-key-press-addition (which-key)
  (setf *addition-answer* (cons which-key *addition-answer*)))


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;</xmp><pre><a name="model">
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;</a>
;;;
;;; The ACT-R model

(clearall)


;;;;;;;;;;;;;
;;;
;;; Define the chunk types for the model

;;; chunk types to represent the goals in the task

(chunk-type add-column
" 
a goal to add the two numbers in a column
 slots:
    number1 - the top number of the column
    number2 - the bottom number of the column
    carry - a possible carry from the previous column
    note - specifies if there is a carry to the next
           column, or if the problem is complete
    answer - holds the sum of the numbers in the column
    column - holds the index of the column currently
             being added
"
 number1 number2 carry note answer column)

(chunk-type addition-problem 
"
a goal to solve an addition problem
 slots:
    column - column holds nil if the problem has not
             been started, otherwise it holds the
             column index of the next column to add
    carry - a value to carry to the next column
"
 column carry) 


;;; chunk types to represent the numbers and the addition facts

(chunk-type addition-fact 
"
a chunk type to represent addend1 + addend2 = sum
"
 addend1 addend2 sum)

(chunk-type number
"
an abstract representation of numbers
 slots:
    tens - the tens digit number wme
    value - the numerical value (i.e. 1 or 2 or 3 ...)
    units - the ones digit number wme
"
 tens value units) 


;;; chunk types to represent the columns and the ordering

(chunk-type index
"
a chunk type to represent the column names
")

(chunk-type next-info 
"
 a chunk type that specifies column index ordering
  slots:
     before - the index that occurs before the index in slot after
     after - the index that occurs after the index in slot before
"
 before after)


;;; general chunk types needed for running the model

(chunk-type visual-object
"
 a chunk type to represent the visual
 locations of the numbers in the problem
  slots:
     row - the row (top or bottom) of a number
     column - the column index of the number 
     value - the number chunk of the number
"
 row column value) 

(chunk-type symbol
"
 general symbols 
")

;;;;;;;;;;;;;;;;;;
;;;
;;; Initialize the working memory for the model
;;;

(add-dm

 ;; label markers for the columns of an addition problem
 
 (ones isa index)
 (tens isa index)
 (hundreds isa index)
 (thousands isa index)
 (ten-thousands isa index)
 (hundred-thousands isa index)
 (millions isa index)

 ;; labels for the row information of the visual-objects

 (top isa index)
 (bottom isa index)
 
 ;; general symbols used in the model

 (finished isa symbol)
 (+ isa symbol)
 
 ;; wmes to indicate the ordering of the column labels
 
 (n1 isa next-info before ones after tens)
 (n2 isa next-info before tens after hundreds)
 (n3 isa next-info before hundreds after thousands)
 (n4 isa next-info before thousands after ten-thousands)
 (n5 isa next-info before ten-thousands after hundred-thousands)
 (n6 isa next-info before hundred-thousands after millions)

 ;;  Memory elements to encode the visual representation of the 
 ;; addition problem:
 ;;                    2 9 3
 ;;                  + 1 2 5



 (i1 isa visual-object
     column ones
     row top
     value three)
 (i2 isa visual-object
     column ones
     row bottom
     value five)
 (i3 isa visual-object
     column tens
     row top
     value nine)
 (i4 isa visual-object
     column tens
     row bottom
     value two)
 (i5 isa visual-object
     column hundreds
     row top
     value two)
 (i6 isa visual-object
     column hundreds
     row bottom
     value one) 
 (i8 isa visual-object
     column thousands
     row bottom
     value +)

;;; wmes to represent the numbers 0-19

 (zero
  isa number
  value 0
  tens zero
  units zero)
 (one 
  isa number
  value 1
  tens zero
  units one)
 (two 
  isa number
  value 2
  tens zero
  units two)
 (three 
  isa number
  value 3
  tens zero
  units three)
 (four 
  isa number
  value 4
  tens zero
  units four)
 (five 
  isa number
  tens zero
  value 5
  units five)
 (six 
  isa number
  tens zero
  value 6
  units six)
 (seven 
  isa number
  tens zero
  value 7
  units seven)
 (eight 
  isa number
  tens zero 
  value 8
  units eight)
 (nine 
  isa number
  tens zero 
  value 9
  units nine)
 (ten 
  isa number
  tens one
  units zero
  value 0)
 (eleven 
  isa number
  tens one
  units one)
 (twelve 
  isa number
  tens one
  units two)
 (thirteen 
  isa number
  tens one
  units three)
 (fourteen 
  isa number
  tens one
  units four)
 (fifteen 
  isa number
  tens one
  units five)
 (sixteen 
  isa number
  tens one
  units six)
 (seventeen 
  isa number
  tens one
  units seven)
 (eightteen 
  isa number
  tens one
  units eight)
 (nineteen 
  isa number
  tens one
  units nine)
 
;;; Addition facts for all sums [0-10] + [0-10]
;;; and 1 + [11-18]

 (fact00
  isa addition-fact
  addend1 zero
  addend2 zero
  sum zero)
 (fact01
  isa addition-fact
  addend1 zero
  addend2 one
  sum one)
 (fact02
  isa addition-fact
  addend1 zero
  addend2 two
  sum two)
 (fact03
  isa addition-fact
  addend1 zero
  addend2 three
  sum three)
 (fact04
  isa addition-fact
  addend1 zero
  addend2 four
  sum four)
 (fact05
  isa addition-fact
  addend1 zero
  addend2 five
  sum five)
 (fact06
  isa addition-fact
  addend1 zero
  addend2 six
  sum six)
 (fact07
  isa addition-fact
  addend1 zero
  addend2 seven
  sum seven)
 (fact08
  isa addition-fact
  addend1 zero
  addend2 eight
  sum eight)
 (fact09
  isa addition-fact
  addend1 zero
  addend2 nine
  sum nine)
 (fact10
  isa addition-fact
  addend1 one
  addend2 zero
  sum one)
 (fact11
  isa addition-fact
  addend1 one
  addend2 one
  sum two)
 (fact12
  isa addition-fact
  addend1 one
  addend2 two
  sum three)
 (fact13
  isa addition-fact
  addend1 one
  addend2 three
  sum four)
 (fact14
  isa addition-fact
  addend1 one
  addend2 four
  sum five)
 (fact15
  isa addition-fact
  addend1 one
  addend2 five
  sum six)
 (fact16
  isa addition-fact
  addend1 one
  addend2 six
  sum seven)
 (fact17
  isa addition-fact
  addend1 one
  addend2 seven
  sum eight)
 (fact18
  isa addition-fact
  addend1 one
  addend2 eight
  sum nine)
 (fact19
  isa addition-fact
  addend1 one
  addend2 nine
  sum ten)
 (fact20
  isa addition-fact
  addend1 two
  addend2 zero
  sum two)
 (fact21
  isa addition-fact
  addend1 two
  addend2 one
  sum three)
 (fact22
  isa addition-fact
  addend1 two
  addend2 two
  sum four)
 (fact23
  isa addition-fact
  addend1 two
  addend2 three
  sum five)
 (fact24
  isa addition-fact
  addend1 two
  addend2 four
  sum six)
 (fact25
  isa addition-fact
  addend1 two
  addend2 five
  sum seven)
 (fact26
  isa addition-fact
  addend1 two
  addend2 six
  sum eight)
 (fact27
  isa addition-fact
  addend1 two
  addend2 seven
  sum nine)
 (fact28
  isa addition-fact
  addend1 two
  addend2 eight
  sum ten)
 (fact29
  isa addition-fact
  addend1 two
  addend2 nine
  sum eleven)
 (fact30
  isa addition-fact
  addend1 three
  addend2 zero
  sum three)
 (fact31
  isa addition-fact
  addend1 three
  addend2 one
  sum four)
 (fact32
  isa addition-fact
  addend1 three
  addend2 two
  sum five)
 (fact33
  isa addition-fact
  addend1 three
  addend2 three
  sum six)
 (fact34
  isa addition-fact
  addend1 three
  addend2 four
  sum seven)
 (fact35
  isa addition-fact
  addend1 three
  addend2 five
  sum eight)
 (fact36
  isa addition-fact
  addend1 three
  addend2 six
  sum nine)
 (fact37
  isa addition-fact
  addend1 three
  addend2 seven
  sum ten)
 (fact38
  isa addition-fact
  addend1 three
  addend2 eight
  sum eleven)
 (fact39
  isa addition-fact
  addend1 three
  addend2 nine
  sum twelve)
 (fact40
  isa addition-fact
  addend1 four
  addend2 zero
  sum four)
 (fact41
  isa addition-fact
  addend1 four
  addend2 one
  sum five)
 (fact42
  isa addition-fact
  addend1 four
  addend2 two
  sum six)
 (fact43
  isa addition-fact
  addend1 four
  addend2 three
  sum seven)
 (fact44
  isa addition-fact
  addend1 four
  addend2 four
  sum eight)
 (fact45
  isa addition-fact
  addend1 four
  addend2 five
  sum nine)
 (fact46
  isa addition-fact
  addend1 four
  addend2 six
  sum ten)
 (fact47
  isa addition-fact
  addend1 four
  addend2 seven
  sum eleven)
 (fact48
  isa addition-fact
  addend1 four
  addend2 eight
  sum twelve)
 (fact49
  isa addition-fact
  addend1 four
  addend2 nine
  sum thirteen)
 (fact50
  isa addition-fact
  addend1 five
  addend2 zero
  sum five)
 (fact51
  isa addition-fact
  addend1 five
  addend2 one
  sum six)
 (fact52
  isa addition-fact
  addend1 five
  addend2 two
  sum seven)
 (fact53
  isa addition-fact
  addend1 five
  addend2 three
  sum eight)
 (fact54
  isa addition-fact
  addend1 five
  addend2 four
  sum nine)
 (fact55
  isa addition-fact
  addend1 five
  addend2 five
  sum ten)
 (fact56
  isa addition-fact
  addend1 five
  addend2 six
  sum eleven)
 (fact57
  isa addition-fact
  addend1 five
  addend2 seven
  sum twelve)
 (fact58
  isa addition-fact
  addend1 five
  addend2 eight
  sum thirteen)
 (fact59
  isa addition-fact
  addend1 five
  addend2 nine
  sum fourteen)
 (fact60
  isa addition-fact
  addend1 six
  addend2 zero
  sum six)
 (fact61
  isa addition-fact
  addend1 six
  addend2 one
  sum seven)
 (fact62
  isa addition-fact
  addend1 six
  addend2 two
  sum eight)
 (fact63
  isa addition-fact
  addend1 six
  addend2 three
  sum nine)
 (fact64
  isa addition-fact
  addend1 six
  addend2 four
  sum ten)
 (fact65
  isa addition-fact
  addend1 six
  addend2 five
  sum eleven)
 (fact66
  isa addition-fact
  addend1 six
  addend2 six
  sum twelve)
 (fact67
  isa addition-fact
  addend1 six
  addend2 seven
  sum thirteen)
 (fact68
  isa addition-fact
  addend1 six
  addend2 eight
  sum fourteen)
 (fact69
  isa addition-fact
  addend1 six
  addend2 nine
  sum fifteen)
 (fact70
  isa addition-fact
  addend1 seven
  addend2 zero
  sum seven)
 (fact71
  isa addition-fact
  addend1 seven
  addend2 one
  sum eight)
 (fact72
  isa addition-fact
  addend1 seven
  addend2 two
  sum nine)
 (fact73
  isa addition-fact
  addend1 seven
  addend2 three
  sum ten)
 (fact74
  isa addition-fact
  addend1 seven
  addend2 four
  sum eleven)
 (fact75
  isa addition-fact
  addend1 seven
  addend2 five
  sum twelve)
 (fact76
  isa addition-fact
  addend1 seven
  addend2 six
  sum thirteen)
 (fact77
  isa addition-fact
  addend1 seven
  addend2 seven
  sum fourteen)
 (fact78
  isa addition-fact
  addend1 seven
  addend2 eight
  sum fifteen)
 (fact79
  isa addition-fact
  addend1 seven
  addend2 nine
  sum sixteen)
 (fact80
  isa addition-fact
  addend1 eight
  addend2 zero
  sum eight)
 (fact81
  isa addition-fact
  addend1 eight
  addend2 one
  sum nine)
 (fact82
  isa addition-fact
  addend1 eight
  addend2 two
  sum ten)
 (fact83
  isa addition-fact
  addend1 eight
  addend2 three
  sum eleven)
 (fact84
  isa addition-fact
  addend1 eight
  addend2 four
  sum twelve)
 (fact85
  isa addition-fact
  addend1 eight
  addend2 five
  sum thirteen)
 (fact86
  isa addition-fact
  addend1 eight
  addend2 six
  sum fourteen)
 (fact87
  isa addition-fact
  addend1 eight
  addend2 seven
  sum fifteen)
 (fact88
  isa addition-fact
  addend1 eight
  addend2 eight
  sum sixteen)
 (fact89
  isa addition-fact
  addend1 eight
  addend2 nine
  sum seventeen)
 (fact90
  isa addition-fact
  addend1 nine
  addend2 zero
  sum nine)
 (fact91
  isa addition-fact
  addend1 nine
  addend2 one
  sum ten)
 (fact92
  isa addition-fact
  addend1 nine
  addend2 two
  sum eleven)
 (fact93
  isa addition-fact
  addend1 nine
  addend2 three
  sum twelve)
 (fact94
  isa addition-fact
  addend1 nine
  addend2 four
  sum thirteen)
 (fact95
  isa addition-fact
  addend1 nine
  addend2 five
  sum fourteen)
 (fact96
  isa addition-fact
  addend1 nine
  addend2 six
  sum fifteen)
 (fact97
  isa addition-fact
  addend1 nine
  addend2 seven
  sum sixteen)
 (fact98
  isa addition-fact
  addend1 nine
  addend2 eight
  sum seventeen)
 (fact99
  isa addition-fact
  addend1 nine
  addend2 nine
  sum eightteen)
 (fact100
  isa addition-fact
  addend1 ten
  addend2 zero
  sum ten)
 (fact101
  isa addition-fact
  addend1 ten
  addend2 one
  sum eleven)
 (fact102
  isa addition-fact
  addend1 ten
  addend2 two
  sum twelve)
 (fact103
  isa addition-fact
  addend1 ten
  addend2 three
  sum thirteen)
 (fact104
  isa addition-fact
  addend1 ten
  addend2 four
  sum fourteen)
 (fact105
  isa addition-fact
  addend1 ten
  addend2 five
  sum fifteen)
 (fact106
  isa addition-fact
  addend1 ten
  addend2 six
  sum sixteen)
 (fact107
  isa addition-fact
  addend1 ten
  addend2 seven
  sum seventeen)
 (fact108
  isa addition-fact
  addend1 ten
  addend2 eight
  sum eightteen)
 (fact109
  isa addition-fact
  addend1 ten
  addend2 nine
  sum nineteen)
(fact111
  isa addition-fact
  addend1 eleven
  addend2 one
  sum twelve)
(fact121
  isa addition-fact
  addend1 twelve
  addend2 one
  sum thirteen)
(fact131
  isa addition-fact
  addend1 thirteen
  addend2 one
  sum fourteen)
(fact141
  isa addition-fact
  addend1 fourteen
  addend2 one
  sum fifteen)
(fact151
  isa addition-fact
  addend1 fifteen
  addend2 one
  sum sixteen)
(fact161
  isa addition-fact
  addend1 sixteen
  addend2 one
  sum seventeen)
(fact171
  isa addition-fact
  addend1 seventeen
  addend2 one
  sum eightteen)
(fact181
  isa addition-fact
  addend1 eightteen
  addend2 one
  sum nineteen)

;;; the main goal of the model

(goal isa addition-problem))

;;; focus on the main goal

(goal-focus goal)


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; PRODUCTIONS 
;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;



(p start-problem
"
  IF the goal is to do an addition problem but no column has
     been identified 
  THEN set a subgoal to add the digits in the ones column
     note that the tens column ins the next one to work on
     and setup the note slot of the new goal to pass a value
     back to the carry slot of the current goal when popped
"
   =goal>
      isa addition-problem
      column nil
==>
   =newgoal>
      isa add-column
      column ones
      note =carry
      carry zero

   =goal>
      column tens
      carry =carry

   !push! =newgoal
)


(p read-number1
"
  IF the goal is to add the numbers in a column and the top number has
     not been read yet
     and there is a number in the top row of the column
  THEN note in the goal that this is one of the numbers to be added
"
   =goal>
      isa add-column
      number1 nil
      column =col

   =object>
      isa visual-object
      value =num1
      row top
      column =col
==>
   =goal>
      number1 =num1
)


(p read-number2
"
  IF the goal is to add the numbers in a column and the bottom number has
     not been read yet
     and there is a number in the bottom row of the column
  THEN note in the goal that this is one of the numbers to be added
"
   =goal>
      isa add-column
      number2 nil
      column =col

   =object>
      isa visual-object
      value =num2
      column =col
      row bottom
==>
   =goal>
      number2 =num2
)


(p add-numbers
"
  IF the goal is to add the numbers in the column
     and both numbers have been read 
     and another number is their sum
  THEN note that other number as the answer
"
   =goal>
      isa add-column
      number1 =num1
      number2 =num2
      answer nil

   =fact>
      isa addition-fact
      addend1 =num1
      addend2 =num2
      sum =sum
==>
   =goal>
      answer =sum
)


(p extract-answer
"
  IF the goal is to add the numbers in the column and the sum has been 
     computed and the sum has a ones digit and a tens digit
  THEN set the answer to the ones digit 
     and note the tens digit as the carry 
"
   =goal>
      isa add-column
      answer =sum
      note nil
      carry zero

   =sum>
      isa number
      tens =num
      units =number1
==>
   =goal>
      answer =number1
      note =num
)


(p process-carry
"
  IF the goal is to add the numbers in the column and there is an 
     answer
     and the column has a carry marked
     and there is a number one greater than the answer
  THEN note in the goal that the answer is the new number  
     and remove the marking of the carry from the goal
"
   =goal>
      isa add-column
      answer =number
      carry one

   =fact>
      isa addition-fact
      addend2 one
      addend1 =number
      sum =new
==>
   =goal>
      answer =new
      carry zero
)


(p write-answer
"
  IF the goal is to add the numbers in the column and there is no carry
     and the answer is a one-digit number
  THEN write the answer and pop the goal (returning the value of the note slot)
"
   =goal>
      isa add-column
      carry zero
      answer =number
      column =col

   =number>
      isa number
      value =value
      tens zero
==>
   !output! ("the answer to column ~s is: ~s~%" =col =value)

   !eval! (store-key-press-addition =value)

   !pop!
)


(p last-column-no-carry
"
  IF the goal is add the numbers in a column and an item has been read into
     the bottom number slot and that item is a +
     and there is no carry to be passed on

  THEN note the goal as finished and pop it (passing the finished back to the
     carry slot of the previous goal)
"
   =goal>
      isa add-column
      number2 +
    - carry one
==>
   =goal>
      note finished
    
   !pop!
)


(p last-column-carry
"
  IF the goal is to add the numbers in a column and an item has been read into
     the bottom number slot and that item is a +
     and there is a carry to be passed on
  THEN write the carry out and note the goal as finished 
     and pop it (passing the finished back to the carry slot of the
     previous goal)
"
   =goal>
      isa add-column
      number2 +
      carry one
      column =col
      carry =carrynum

   =carrynum>
      isa number
      value =val
==>
   !output! ("the answer to column ~s is: ~s~%" =col =val)

   !eval! (store-key-press-addition =val)

   =goal>
      note finished
    
   !pop!
)


(p next-column
"
  IF the goal is to do an addition problem and the problem has not
     been marked as finished and there is a column after this one
  THEN note that the current column is the one on which you are working
     and set a subgoal to add the digits in that column
     and note in the current goal which is the next column
     and setup the note slot of the new goal to pass a value
     back to the carry slot of the current goal when popped
"
   =goal>
      isa addition-problem
      column =pos1
    - carry finished
      carry =carry

   =next>
      isa next-info
      before =pos1
      after =pos2
==>
   =newgoal>
      isa add-column
      column =pos1
      carry =carry
      note =newcarry

   =goal>
      column =pos2
      carry =newcarry
    
   !push! =newgoal
)


(p stop-problem
"
  IF the goal is to do an addition problem and the problem has been
     marked as finished
  THEN pop the goal
"
   =goal>
      isa addition-problem
      carry finished
==>
   !pop!
)