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21 lines
634 B
21 lines
634 B
2 years ago
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Exercise 3.35: Ben Bitdiddle tells Louis that
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one way to avoid the trouble in Exercise 3.34 is to define a squarer as a
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new primitive constraint. Fill in the missing portions in Ben’s outline for a
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procedure to implement such a constraint:
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(define (squarer a b)
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(define (process-new-value)
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(if (has-value? b)
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(if (< (get-value b) 0)
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(error "square less than 0:
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SQUARER"
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(get-value b))
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⟨alternative1⟩)
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⟨alternative2⟩))
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(define (process-forget-value) ⟨body1⟩)
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(define (me request) ⟨body2⟩)
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⟨rest of definition⟩
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me)
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