I have a group of high school students with a question... can someone please explain to beginner Racket users the differences between these three boolean functions: eq? equal? eqv?
We have read the help menu verbage visible from DrRacket, but simply don't understand what it is saying. Maybe that's lack of context or vocabulary... but we're struggling a bit. To test simple variations of application, we wrote some simple code (shown below) but don't understand why the results are what they are: (define FOUR "four") (define A (make-posn 4 5)) (define B (make-posn (+ 3 1) (- 6 1))) "-------------" (equal? FOUR "four") (equal? 4 (+ 1 3)) (equal? 4 (posn-x (make-posn 4 3))) (equal? A B) "-------------" (eq? FOUR "four") (eq? 4 (+ 1 3)) (eq? 4 (posn-x (make-posn 4 3))) (eq? A B) "---------------" (eqv? FOUR "four") (eqv? 4 (+ 1 3)) (eqv? 4 (posn-x (make-posn 4 3))) (eqv? A B) Why in the world would the above-defined A and B be considered "equal?" but not "eq?" or "eqv?"? -- *Joe Ford Technology Resources, Scheduling & Yearbook Holland Hall jf...@hollandhall.org *
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