18 lines
964 B
Racket
18 lines
964 B
Racket
#lang syndicate/actor
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;; Toy file system, based on the example in the ESOP2016 submission.
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;; syndicate/actor implementation, using "during" instead of "on asserted/until retracted".
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(require/activate "fs-shell.rkt")
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(require/activate "fs-protocol.rkt")
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(actor (react (field [files (hash)])
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(during (observe (file $name _))
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(on-start (printf "At least one reader exists for ~v\n" name))
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(on-stop (printf "No remaining readers exist for ~v\n" name))
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(field [content (hash-ref (files) name #f)])
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(assert (file name (content)))
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(on (message (save (file name $new-content))) (content new-content))
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(on (message (delete name)) (content #f)))
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(on (message (save (file $name $content))) (files (hash-set (files) name content)))
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(on (message (delete $name)) (files (hash-remove (files) name)))))
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