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;;; Read-Eval-Print Loop
;; Copyright (C) 2001 Free Software Foundation, Inc.
;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; see the file COPYING. If not, write to
;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Code:
(define-module (system repl repl)
:use-syntax (system base syntax)
:use-module (system base pmatch)
:use-module (system base compile)
:use-module (system base language)
:use-module (system repl common)
:use-module (system repl command)
:use-module (system vm core)
:use-module (system vm debug)
:use-module (ice-9 rdelim)
:export (start-repl))
(define meta-command-token (cons 'meta 'command))
(define (meta-reader read)
(lambda read-args
(with-input-from-port
(if (pair? read-args) (car read-args) (current-input-port))
(lambda ()
(if (eqv? (next-char #t) #\,)
(begin (read-char) meta-command-token)
(read))))))
;; repl-reader is a function defined in boot-9.scm, and is replaced by
;; something else if readline has been activated. much of this hoopla is
;; to be able to re-use the existing readline machinery.
(define (prompting-meta-read repl)
(let ((prompt (lambda () (repl-prompt repl)))
(lread (language-reader (repl-language repl))))
(with-fluid* current-reader (meta-reader lread)
(lambda () (repl-reader (lambda () (repl-prompt repl)))))))
(define (default-pre-unwind-handler key . args)
(save-stack default-pre-unwind-handler)
(apply throw key args))
(define (default-catch-handler . args)
(pmatch args
((quit . _)
(apply throw args))
((vm-error ,fun ,msg ,args)
(display "VM error: ")
(apply format #t msg args)
(vm-backtrace (the-vm))
(newline))
((,key ,subr ,msg ,args . ,rest)
(let ((cep (current-error-port)))
(cond ((not (stack? (fluid-ref the-last-stack))))
((memq 'backtrace (debug-options-interface))
(let ((highlights (if (or (eq? key 'wrong-type-arg)
(eq? key 'out-of-range))
(car rest)
'())))
(run-hook before-backtrace-hook)
(newline cep)
(display "Backtrace:\n")
(display-backtrace (fluid-ref the-last-stack) cep
#f #f highlights)
(newline cep)
(run-hook after-backtrace-hook))))
(run-hook before-error-hook)
(apply display-error (fluid-ref the-last-stack) cep subr msg args rest)
(run-hook after-error-hook)
(set! stack-saved? #f)
(force-output cep)))
(else
(apply bad-throw args))))
(eval-case
((compile-toplevel)
(define-macro (start-stack tag expr)
expr)))
(define (start-repl lang)
(let ((repl (make-repl lang)))
(repl-welcome repl)
(let prompt-loop ()
(let ((exp (prompting-meta-read repl)))
(cond
((eq? exp meta-command-token)
(meta-command repl (read-line)))
((eof-object? exp)
(throw 'quit))
(else
(catch #t
(lambda ()
(call-with-values (lambda ()
(run-hook before-eval-hook exp)
(start-stack repl-eval
(repl-eval repl exp)))
(lambda l
(for-each (lambda (v)
(run-hook before-print-hook v)
(repl-print repl v))
l))))
default-catch-handler
default-pre-unwind-handler)))
(next-char #f) ;; consume trailing whitespace
(prompt-loop)))))
(define (next-char wait)
(if (or wait (char-ready?))
(let ((ch (peek-char)))
(cond ((eof-object? ch) (throw 'quit))
((char-whitespace? ch) (read-char) (next-char wait))
(else ch)))
#f))
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