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2.8 Subtraction of intervals
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Looks like the solution (substracting lower with lower, upper with upper) is wrong |
2022-12-12 |
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2.59 Union-set for sets represented as unordered lists
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The order shouldn't matter when validating the solution. E.g. below code should be correct but doesn't pass the test
(define (union-set s1 s2)
(if (null? s2)
s1
(union-set (adjoin-set (car s2) s1) (cdr s2))
)
)
The function adjoin-set is defined in book. |
2023-01-15 |
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4.5 Modify the handling of cond
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I think the test code won't work as expected. For example, when running the first test case
(check-equal? (eval (cond ((assoc 'b '((a 1) (b 2))) => cadr) (else #f)) the-global-environment) 2)
The cond will be evaluated before calling eval (applicative order). In other words, the above test case will actually be
(check-equal? (eval 2 the-global-environment) 2)
When calling eval, the formal parameter exp will be 2, not a list expected |
2023-02-23 |