25 lines
788 B
Racket
25 lines
788 B
Racket
#lang racket/base
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(provide message-struct
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assertion-struct
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(struct-out observe)
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(struct-out seal)
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(struct-out inbound)
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(struct-out outbound))
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;; Thin veneers over `struct` for declaring intent.
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(define-syntax-rule (assertion-struct item ...) (struct item ... #:prefab))
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(define-syntax-rule (message-struct item ...) (struct item ... #:prefab))
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(assertion-struct observe (specification))
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;; Seals are used by protocols to prevent routing from examining
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;; internal structure of values.
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(struct seal (contents) ;; NB. Neither transparent nor prefab
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#:methods gen:custom-write
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[(define (write-proc s port mode)
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(fprintf port "#{~v}" (seal-contents s)))])
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(struct inbound (assertion) #:prefab)
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(struct outbound (assertion) #:prefab)
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