14 lines
233 B
Racket
14 lines
233 B
Racket
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#lang racket
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(define/contract x
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(=/c 42) ; make sure x = 42
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42)
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(define/contract f
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(-> number? (or/c 'yes 'no)) ; function contract
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(lambda (x)
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(if (= 42 x) 'yes 'no)))
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(f 42) ; succeeds
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(f "foo") ; contract error!
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