14 lines
402 B
Scheme
14 lines
402 B
Scheme
(module only-once mzscheme
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(provide maybe-print-message)
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(define already-printed? #f)
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(define (maybe-print-message msg)
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(unless already-printed?
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(set! already-printed? #t)
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;; the output port may no longer be there, in which case
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;; we just give up on printing
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(with-handlers ([exn:fail? (lambda (x) (void))])
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(fprintf (current-error-port) "~a" msg)))))
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