20 lines
408 B
Racket
20 lines
408 B
Racket
#lang racket
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;; data definitions
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(define id? symbol?)
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(define id-equal? eq?)
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(define-struct basic-customer (id name address) #:mutable)
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;; interface
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(provide/contract
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[id? (-> any/c boolean?)]
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[id-equal? (-> id? id? boolean?)]
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[struct basic-customer ((id id?)
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(name string?)
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(address string?))])
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;; end of interface
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