77 lines
2.4 KiB
Scheme
77 lines
2.4 KiB
Scheme
(define-library (picrin repl)
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(import (scheme base)
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(scheme read)
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(scheme write)
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(scheme eval)
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(picrin base))
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(cond-expand
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((library (picrin readline))
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(import (picrin readline)
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(picrin readline history)))
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(else
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(begin
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(define (readline str)
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(when (tty?)
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(display str)
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(flush-output-port))
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(read-line))
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(define (add-history str)
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#f))))
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(define user-env (library-environment (find-library '(picrin user))))
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(begin
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(current-library (find-library '(picrin user)))
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(eval
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'(import (scheme base)
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(scheme load)
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(scheme process-context)
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(scheme read)
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(scheme write)
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(scheme file)
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(scheme inexact)
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(scheme cxr)
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(scheme lazy)
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(scheme time)
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(picrin macro))
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user-env)
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(current-library (find-library '(picrin repl))))
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(define (repl)
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(let loop ((buf ""))
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(let ((line (readline (if (equal? buf "") "> " ""))))
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(if (eof-object? line)
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(newline) ; exit
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(let ((str (string-append buf line "\n")))
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(add-history line)
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(call/cc
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(lambda (exit)
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(with-exception-handler
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(lambda (condition)
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(if (error-object? condition)
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(unless (equal? (error-object-message condition) "unexpected EOF")
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(display "error: ")
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(display (error-object-message condition))
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(newline)
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(set! str ""))
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(begin
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(display "raised: ")
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(write condition)
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(newline)
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(set! str "")))
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(exit))
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(lambda ()
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(call-with-port (open-input-string str)
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(lambda (port)
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(let next ((expr (read port)))
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(unless (eof-object? expr)
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(write (eval expr user-env))
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(newline)
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(set! str "")
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(next (read port))))))))))
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(loop str))))))
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(export repl))
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