1 / 22

Environment Model Examples

Environment Model Examples. Prof. Tony White April 2010. Ref: http://www.cs.caltech.edu/courses/cs1/resources/environment-model-tutorial/environments.html. Example 1. 1. (define ( foo x ) (+ x 1)) 2. ( foo 2). f oo ’. Π =1. Π =3. Example 2. (let (( x 1)

abraham-taylor
Download Presentation

Environment Model Examples

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Environment Model Examples Prof. Tony White April 2010 Ref: http://www.cs.caltech.edu/courses/cs1/resources/environment-model-tutorial/environments.html

  2. Example 1 1. (define (foox) (+ x 1)) 2. (foo 2) foo’ Π=1 Π=3

  3. Example 2 (let ((x 1) (y 2)) (+ xy)) let’ Π=3 Π=4

  4. Example 3 1. (lambda (xy) (+ xy)) 1 2) lambda’ Π=1 Π=2

  5. (define (sqrtff) (lambda (x) (sqrt (fx)))) (define (inc n) (+ n 1)) (define f1 (sqrtf inc)) (f1 3) Example 4-a Π=4

  6. (define (sqrtff) (lambda (x) (sqrt (fx)))) (define (inc n) (+ n 1)) (define f1 (sqrtf inc)) (f1 3) Example 4-b sqrtf’ Π=5

  7. (define (sqrtff) (lambda (x) (sqrt (fx)))) (define (inc n) (+ n 1)) (define f1 (sqrtf inc)) (f1 3) Example 4-c sqrtf’ f1’ Π=2 Π=6

  8. (define (sqrtff) (lambda (x) (sqrt (fx)))) (define (inc n) (+ n 1)) (define f1 (sqrtf inc)) (f1 3) Example 4-d sqrtf’ f’ f1’ Π=3 Π=2 Π=6

  9. (define bar (let ((x 1) (y 2)) (lambda (z) (+ xyz)))) (bar 3) Example 5-a let’ Π=5

  10. (define bar (let ((x 1) (y 2)) (lambda (z) (+ xyz)))) (bar 3) Example 5-b let’ bar’ Π=4 Π=6

  11. Example 6: Code (define (fooz) (let ((xz)) (let ((y (+ xz))) (lambda (sym) (cond ((eq? sym 'x) x) ((eq? sym 'y) y) ((eq? sym 'bump-x) (set! x (+ xz))) ((eq? sym 'bump-y) (set! y (+ yz))) ((eq? sym 'reset-x) (set! x 0)) ((eq? sym 'reset-y) (set! y 0))))))) (define f (foo 10)) (f 'x) (f 'y) (f 'bump-x) ; Rest of code not shown

  12. Example 6-a foo’ Π=12

  13. Example 6-b foo’ Π=5 Π=13

  14. Example 6-c foo’ Π=7 Π=15

  15. Example 6-d • Rest of code associated with example 6 left as an exercise to the reader. It really is a set of variations on 6-b and 6-c.

  16. Example 7: Code (define (new-sqrtx) (define (good-enough? guess) (< (abs (- (square guess) x)) 0.000001)) (define (average xy) (/ (+ xy) 2)) (define (improve guess) (average guess (/ x guess))) (define (sqrt-iter guess) (if (good-enough? guess) guess (sqrt-iter (improve guess)))) (sqrt-iter 1.0)) (new-sqrt 2.0)

  17. Example 7-a Π=13

  18. Example 7-b new-sqrt’ Π=12 Π=14

  19. Example 7-c new-sqrt’ sqrt-iter’ Π=12 Π=14 Π=9

  20. (define (foox) (let ((y (lambda (w) (+ xw))) (z (lambda (w) (* xw)))) (y (zx)))) (foo 10) Example 8-a Π=5

  21. (define (foox) (let ((y (lambda (w) (+ xw))) (z (lambda (w) (* xw)))) (y (zx)))) (foo 10) Example 8-b foo’ Π=2 Π=6

  22. (define (foox) (let ((y (lambda (w) (+ xw))) (z (lambda (w) (* xw)))) (y (zx)))) (foo 10) Example 8-c foo’ let’ Π=6 Π=4 Π=2

More Related