;;; 6.945 Problem Set #3 Scheme Code
;;; 02/25/2009
;;; Bryan Newbold

; Note: See the attached bnewbold_ps3.txt for comments

; This file should be loaded into the generic-evaluation-environment

;;; Problem 3.1

(defhandler apply
  (lambda (proc-vector ops env)
    (vector-map
     (lambda (proc)
       (apply proc ops env))
     proc-vector))
  (lambda (thing)
    (and (vector? thing)
	 (not (compound-procedure? thing)))))

(define add1 (lambda (x) (+ 1 x)))

#| Test 
eval> (define cube (lambda (x) (* x x x)))
cube

eval> (cube 3)
27 

eval> ((vector cube sin cos sqrt) 1)
#(1 .8414709848078965 .5403023058681398 1)
|#

;;; Problem 3.2

(define ALLOW-SELF-EVALUATING-SYMBOLS #t)

(define (unbound-symbol? s)
  (if (symbol? s)
      (eq? 'unbound (environment-reference-type 
		     (nearest-repl/environment)
		     s))
      #f))

(define ((binary-pass symbol) a b)
  (if (not ALLOW-SELF-EVALUATING-SYMBOLS)
      (error "We don't ALLOW-SELF-EVALUATING-SYMBOLS!")
      (if (for-all? 
	      (list a b)
	    (lambda (x)
	      (or (number? x) 
		  (unbound-symbol? x)
		  (and (list? x) 
		       (not (null? x))
		       (or (member (car x) (list '+ '* '/ '-))
			   (literal-function? (car x))))))) ; see below
	  (list symbol a b)
	  (error "Not a number or symbol: " a b))))


(define add (make-generic-operator 2 (binary-pass '+)))
(define multiply (make-generic-operator 2 (binary-pass '*)))
(define divide (make-generic-operator 2 (binary-pass '/)))
(define subtract (make-generic-operator 2 (binary-pass '-)))

(defhandler add + number? number?)
(defhandler multiply * number? number?)
(defhandler divide / number? number?)
(defhandler subtract - number? number?)



#| Test:
(add (multiply 42 5365) (add (subtract 'a 3) (divide 4 5)))
;Value: (+ 225330 (+ (- a 3) 4/5))
(add (multiply 42 5365) (add (subtract 'a cos) (divide 4 5)))
;Not a number or symbol:  a #[compiled-procedure 69 ("arith" #xce) #xf #x1c05fb]
|#

(define *literal-functions* '())

(define (declare-literal-function f)
  (if (and (symbol? f) (< (string-length (symbol->string f)) 2))
      (begin
	(set! *literal-functions* (cons (environment-define
					 (nearest-repl/environment)
					 f
					 f)
					*literal-functions*))
	(display 
	 "Okey-doke, it is now a literal function"))
      (error "Not a good function name (make it short): " f)))

(define (literal-function? f)
  (if (member f *literal-functions*)
      #t
      #f))

(defhandler apply (lambda (f opts env)
		    (if ALLOW-SELF-EVALUATING-SYMBOLS
			(cons f (evaluate-list opts env))
			(error "We don't ALLOW-SELF-EVALUATING-SYMBOLS: " f)))
  literal-function?)

(defhandler eval (lambda (e env) e)
  literal-function?)

#| Test: TODO COPY
#|
eval> (declare-literal-function 'a)
Okey-doke, it is now a literal function#!unspecific

eval> a
a

eval> (a 2 4 5)
(a 2 4 5)

eval> (add (a 1 2) 'b)
(+ (a 1 2) b)

eval> (multiply (a (add 3 4) 'b) 99)
(* (a 7 b) 99)
|#
|#

;;; Problem 3.3

(define add-streams
  (lambda (a b)
    (kons (+ (car a) (car b))
	  (add-streams (cdr a) (cdr b)))))

(define ref-stream
  (lambda (s n)
    (if (= n 0)
	(car s)
	(ref-stream (cdr s) (- n 1)))))

(define (map-stream proc items)
  (kons (proc (car items))
	(map-stream proc (cdr items))))

(define (scale-stream items factor)
  (map-stream (lambda (x) (* x factor))
	      items))

#| type these in manually to the eval> prompt

(define (integral (integrand lazy) initial-value dt)
    (define int
    (kons initial-value
            (add-streams (scale-stream integrand dt)
                        int)))
    int)
; integral
(define (solve f y0 dt)
    (define y (integral dy y0 dt))
    (define dy (map-stream f y))
    y)
; solve
(ref-stream (solve (lambda (x) x) 1 0.001) 1000)
; 2.716923932235896

|#

;;; Problem 3.4a

(define some-options (list 'beef
			   'thai 'indian 'pasta 'sandwich
			   'crepes 'mexican)) ; len=7

#|
(define whats-for-dinner
  (kons (list-ref some-options (random-integer 7))
	whats-for-dinner))


(define (mealplan w)
  (pp (car w))
  (mealplan (cdr w)))

; Test: 

eval> (mealplan whats-for-dinner)
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
sandwich
...etc

;That's depressing!

|#


;;; Problem 3.5

; Profiling!

(define PROFILING-ENABLED #f)

(define *primative-call-database*
  (make-eq-hash-table))

(define *compound-call-database*
  (make-eq-hash-table))

(define (print-profile-results)
  (set! PROFILING-ENABLED #f)
  (begin
    (display "----------- Profiling Results ---------------") (newline)
    (display "Primative Procedures:") (newline)
    (hash-table/for-each *primative-call-database*
			 (lambda (key val)
			   (display "   ")
			   (display val)
			   (display "    ")
			   (display key) (newline)))
    (display "Compound Procedures:") (newline)
    (hash-table/for-each *compound-call-database*
			 (lambda (key val)
			   (display "   ")
			   (display val)
			   (display "    ")
			   (display key) (newline)))
    (display "----------- End of Table ---------------") (newline)
    (set! PROFILING-ENABLED #t)))
 
(define ppr print-profile-results) ; shorter


(define (count-primative proc)
  (hash-table-set! *primative-call-database*
		   proc
		   (+ 1 (hash-table-ref/default *primative-call-database*
						proc
						0))))

(define (count-compound proc)
  (hash-table-set! *compound-call-database*
		   proc
		   (+ 1 (hash-table-ref/default *compound-call-database*
						proc
						0))))

; from rtdata:
(define strict-primative-procedure? procedure?)

(defhandler apply 
  (lambda (proc opers env)
    (if PROFILING-ENABLED (count-primative proc))
    (apply-primitive-procedure proc
			       (evaluate-list opers env)))
  strict-primative-procedure?)

(defhandler apply
  (lambda (procedure operands calling-environment)
    (if PROFILING-ENABLED (count-compound procedure))
    (if (not (= (length (procedure-parameters procedure))
		(length operands)))
	(error "Wrong number of operands supplied"))
    (let ((arguments
	   (map (lambda (parameter operand)
		  (evaluate-procedure-operand parameter
					      operand
					      calling-environment))
		(procedure-parameters procedure)
		operands)))
      (eval (procedure-body procedure)
	    (extend-environment
	     (map procedure-parameter-name
		  (procedure-parameters procedure))
	     arguments
	     (procedure-environment procedure)))))
  compound-procedure?)

#| Testing

;; the order is a little off here, I cherry picked out examples from a
;; session so the actual counts are off a bit

(init)
eval> (ppr)
----------- Profiling Results ---------------
Primative Procedures:
Compound Procedures:
----------- End of Table ---------------

eval> (define cube (lambda (x) (* x x x)))
cube

eval> (cube 12)
1728

eval> (ppr)
----------- Profiling Results ---------------
Primative Procedures:
   2    #[compound-procedure 18 print-profile-results]
   1    #[arity-dispatched-procedure 20]
   1    #[arity-dispatched-procedure 19]
Compound Procedures:
   1    #(compound-procedure (x) (* x x x) #((cube) (#(compound-procedure (x) (*
 x x x) #((cube) (#(compound-procedure (x) (* x x x) #((cube) (#(compound-proced
ure ... ... ...)) ()))) ()))) ()))
----------- End of Table ---------------

eval> (define (fib n) (if (< n 2) 1 (+ (fib (- n 2)) (fib (- n 1))))))
fib

eval> (fib 12)
233

eval> (ppr)
----------- Profiling Results ---------------
Primative Procedures:
   1    #[compound-procedure 21 operator]
   13134    #[arity-dispatched-procedure 19]
   1    #[compound-procedure 22 operator]
   1    #[arity-dispatched-procedure 20]
   26168    #[arity-dispatched-procedure 23]
   5    #[compound-procedure 18 print-profile-results]
   26173    #[arity-dispatched-procedure 24]
Compound Procedures:
   1    #(compound-procedure (x) (* x x x) #((fib cube) (#(compound-procedure (n) (if (< n 2) 1 (+ (fib (- n 2)) (fib (- n 1)))) #((fib cube) (#(compound-procedure (n) (if (< n 2) 1 (+ (fib ...) (fib ...))) #((fib cube) (#(compound-procedure ... ... ...) #(compound-procedure ... ... ...)) ())) #(compound-procedure (x) (* x x x) #((fib cube) (#(compound-procedure ... ... ...) #(compound-procedure ... ... ...)) ()))) ())) #(compound-procedure (x) (* x x x) #((fib cube) (#(compound-procedure (n) (if (< n 2) 1 (+ (fib ...) (fib ...))) #((fib cube) (#(compound-procedure ... ... ...) #(compound-procedure ... ... ...)) ())) #(compound-procedure (x) (* x x x) #((fib cube) (#(compound-procedure ... ... ...) #(compound-procedure ... ... ...)) ()))) ()))) ()))
   26172    #(compound-procedure (n) (if (< n 2) 1 (+ (fib (- n 2)) (fib (- n 1)))) #((fib cube) (#(compound-procedure (n) (if (< n 2) 1 (+ (fib (- n 2)) (fib (- n 1)))) #((fib cube) (#(compound-procedure (n) (if (< n 2) 1 (+ (fib ...) (fib ...))) #((fib cube) (#(compound-procedure ... ... ...) #(compound-procedure ... ... ...)) ())) #(compound-procedure (x) (* x x x) #((fib cube) (#(compound-procedure ... ... ...) #(compound-procedure ... ... ...)) ()))) ())) #(compound-procedure (x) (* x x x) #((fib cube) (#(compound-procedure (n) (if (< n 2) 1 (+ (fib ...) (fib ...))) #((fib cube) (#(compound-procedure ... ... ...) #(compound-procedure ... ... ...)) ())) #(compound-procedure (x) (* x x x) #((fib cube) (#(compound-procedure ... ... ...) #(compound-procedure ... ... ...)) ()))) ()))) ()))
----------- End of Table ---------------

|#