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20 lines
476 B
Racket
20 lines
476 B
Racket
7 years ago
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#lang br
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(require data/collection racket/private/generic-methods)
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(define countable<%>
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(interface* ()
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([(generic-property gen:countable)
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(generic-method-table gen:countable
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(define (length o)
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(send o length)))])))
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(define c (class* object% (countable<%>)
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(super-new)
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(define/public (length) 42)))
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c
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(define o (make-object c))
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(length o)
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