35 lines
1.2 KiB
Scheme
35 lines
1.2 KiB
Scheme
#lang scheme/base
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(require scheme/promise)
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(provide (all-from-out scheme/base scheme/promise))
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(define (show x p)
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(let show ([x x])
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(cond [(or (void? x) (not x) (null? x)) (void)]
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[(pair? x) (show (car x)) (show (cdr x))]
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[(promise? x) (show (force x))]
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[(keyword? x) (show (keyword->string x))]
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[(and (procedure? x) (procedure-arity-includes? x 0)) (show (x))]
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;; display won't work, since it calls us back
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;; [else (display x p)]
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;; things that are printed directly
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[(bytes? x) (write-bytes x p)]
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[(string? x) (write-string x p)]
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[(char? x) (write-char x p)]
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[(number? x) (write x p)]
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;; generic fallback
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[else (show (format "~a" x))])))
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;; this is too much -- it also changes error messages
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;; (global-port-print-handler show)
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(port-display-handler (current-output-port) show)
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;; the default prints a newline too, avoid that
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(current-print display)
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;; make it possible to use this language through a repl
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;; --> won't work: need an `inside' reader that reads a single expression
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;; (require (prefix-in * "text/lang/reader.ss"))
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;; (current-prompt-read
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;; (lambda () (parameterize ([read-accept-reader #t]) (*read-syntax))))
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