52 lines
2.1 KiB
Racket
52 lines
2.1 KiB
Racket
#lang minimart
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(require racket/set)
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(require (only-in racket/string string-trim))
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(require "../drivers/tcp.rkt")
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(require "../demand-matcher.rkt")
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(struct session (seen-remote? peers) #:transparent)
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(define (spawn-session them us)
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(define user (gensym 'user))
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(define remote-detector (compile-gestalt-projection (?!)))
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(define peer-detector (compile-gestalt-projection `(,(?!) says ,?)))
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(define (send-to-remote fmt . vs)
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(send #:meta-level 1 (tcp-channel us them (string->bytes/utf-8 (apply format fmt vs)))))
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(define (say who fmt . vs)
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(unless (equal? who user) (send-to-remote "~a ~a\n" who (apply format fmt vs))))
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(list (send-to-remote "Welcome, ~a.\n" user)
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(spawn (lambda (e state)
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(match e
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[(message (tcp-channel _ _ bs) 1 #f)
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(transition state (send `(,user says ,(string-trim (bytes->string/utf-8 bs)))))]
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[(message `(,who says ,what) 0 #f)
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(transition state (say who "says: ~a" what))]
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[(routing-update g)
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(match-define (session seen-remote? old-peers) state)
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(define remote-present?
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(not (matcher-empty? (gestalt-project g 1 0 #f remote-detector))))
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(define new-peers (matcher-key-set/single (gestalt-project g 0 0 #t peer-detector)))
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(transition
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(struct-copy session state
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[seen-remote? (or remote-present? seen-remote?)]
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[peers new-peers])
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(list (when (and seen-remote? (not remote-present?)) (quit))
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(for/list [(who (set-subtract new-peers old-peers))] (say who "arrived."))
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(for/list [(who (set-subtract old-peers new-peers))] (say who "departed."))))]
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[#f #f]))
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(session #f (set))
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(gestalt-union (sub `(,? says ,?))
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(sub `(,? says ,?) #:level 1)
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(pub `(,user says ,?))
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(sub (tcp-channel them us ?) #:meta-level 1)
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(pub (tcp-channel us them ?) #:meta-level 1)
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(pub (tcp-channel us them ?) #:meta-level 1 #:level 1)))))
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(spawn-tcp-driver)
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(spawn-world
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(spawn-demand-matcher (tcp-channel (?! (tcp-address ? ?)) (?! (tcp-listener 5999)) ?)
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#:meta-level 1
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#:demand-is-subscription? #f
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spawn-session))
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