23 lines
535 B
Text
23 lines
535 B
Text
(define-syntax-rule
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(if2 cond1 cond2 both cond1-only cond2-only none) ;; new syntax
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;; will expand to :
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(if cond1
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(if cond2 both cond1-only)
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(if cond2 cond2-only none)))
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→ #syntax:if2
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(define (num-test n)
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(if2 (positive? n) (exact? n)
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"positive and exact"
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"positive and inexact"
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"negative and exact"
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"negative and inexact"))
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(num-test 3/4)
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→ "positive and exact"
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(num-test -666)
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→ "negative and exact"
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(num-test -666.42)
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→ "negative and inexact"
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(num-test PI)
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→ "positive and inexact"
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