50 lines
2.1 KiB
Racket
50 lines
2.1 KiB
Racket
#lang syndicate
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;; Simple "shell" or REPL, used by the file-system demos.
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(require (only-in racket/port read-bytes-line-evt))
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(require (only-in racket/string string-trim string-split))
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(require/activate syndicate/drivers/timer)
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(require/activate "fs-protocol.rkt")
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(define (sleep sec)
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(define timer-id (gensym 'sleep))
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(until (message (timer-expired timer-id _))
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(on-start (send! (set-timer timer-id (* sec 1000.0) 'relative)))))
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;; Shell
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(let ((e (read-bytes-line-evt (current-input-port) 'any)))
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(define (print-prompt)
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(printf "> ")
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(flush-output))
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(spawn (field [reader-count 0])
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(on-start (print-prompt))
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(stop-when (message (inbound (external-event e (list (? eof-object? _))))))
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(on (message (inbound (external-event e (list (? bytes? $bs)))))
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(match (string-split (string-trim (bytes->string/utf-8 bs)))
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[(list "open" name)
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(define reader-id (reader-count))
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(reader-count (+ (reader-count) 1))
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(spawn (on-start (printf "Reader ~a opening file ~v.\n" reader-id name))
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(stop-when (message `(stop-watching ,name)))
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(on (asserted (file name $contents))
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(printf "Reader ~a sees that ~v contains: ~v\n"
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reader-id
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name
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contents))
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(on-stop (printf "Reader ~a closing file ~v.\n" reader-id name)))]
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[(list "close" name)
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(send! `(stop-watching ,name))]
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[(list* "write" name words)
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(send! (save (file name words)))]
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[(list "delete" name)
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(send! (delete name))]
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[_
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(printf "I'm afraid I didn't understand that.\n")
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(printf "Try: open filename\n")
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(printf " close filename\n")
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(printf " write filename some text goes here\n")
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(printf " delete filename\n")])
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(sleep 0.1)
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(print-prompt))))
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