18 lines
456 B
Racket
18 lines
456 B
Racket
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#lang syndicate/actor
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(provide stop-when-duplicate)
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(require syndicate/protocol/instance)
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(require "util.rkt")
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(define (stop-when-duplicate spec)
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(define id (random-hex-string 16))
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(field [duplicate? #f])
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(stop-when (rising-edge (duplicate?)))
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(assert (instance id spec))
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(on (asserted (instance $id2 spec))
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(when (string<? id id2)
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(log-info "Duplicate instance of ~v detected; terminating" spec)
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(duplicate? #t)))
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id)
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