1. 5
(Symbolic Information)

2. Scheme
(symbols)
(strings)
((keyboard)characters)
(images)

3. (Symbols)
.
'the 'a 'chocolate 'cat! 'two^3 'and%so%on?
, .

4. Symbols
symbol=?

5. example

6. "the dog" "isn't" "made of" "two^3" "and so on?"
string=?

8. ex 5.1.2

9. ex 5.1.3

10. 6 1
struct Point{
int x;
int y;
}
(make-posn 3 4)
(posn-x (make-posn 7 0))
(posn-y (make-posn 7 0))

11. structure
(define a-posn (make-posn 7 0))
(posn-x a-posn)
(posn-y a-posn)
(* (posn-x a-posn) 7)
(+ (posn-y a-posn) 13)

12. distance exam
c = sqrt(a^2 + b^2)
sqr, sqrt
(define (distance-to-0 a-posn)
...

13. ex 6.2.1

14. ex 6.2.2

15. 6.3
(define-struct posn (x y))
make-posn : constructor
posn-x : selector
posn-y : selector

16. structure
(define-struct entry (name zip phone))
(make-entry 'PeterLee 15270 '606-7771)
(entry-name (make-entry 'Peter 15270 '606))
= 'Peter

17. rock star example
(define-struct star (last first instrument sales))
make-star, star-last, star-first, star-instrument,
star-sales
(make-star 'lena 'Park 'ukelele 19004)
(star-first E)

18. rock star example
(define-struct star (last first instrument sales))
make-star, star-last, star-first, star-instrument,
star-sales
(make-star 'lena 'Park 'ukelele 19004)
(star-first E)

19. rock star ex
20,000 .
, ,

20. rock star ex
20,000 .
, ,

21. 6.4
DrRacket .
. -> ?

22. 6.5 (Compound)
-p81

23. 7
numbers, booleans, symbols, structures
2 ?

24. 71
.
number?
boolean?
symbol?
struct?

25. Structures
posn?
star?
airplane?

26. distance-to-0 ex
(make-posn 6 6)
(make-posn 1 2)
1, 2, 3
pixel-2
number, posn 2

27. distance-to-0 ex
, ,

28. shape example
(make-square p s) ; p->posn, s->number
(make-circle p s) ; p->posn, s->number

29. shape example
,

30. ex 71.2
.

31. 7.2 (Mixed)
,

33. 7.3
.

34. 7.3
.

35. 7.5
(error 'checked-area-of-disk "number expected")

36. error
execption

37. 8
=> Vocabulary + Grammar
=> (Syntax)
(Semantics) .

38. 8.1 Scheme

39. 8.2 Scheme