guile/step1_read_print.scm

   1 ;;  Copyright (C) 2015
   2 ;;      "Mu Lei" known as "NalaGinrut" <NalaGinrut@gmail.com>
   3 ;;  This file is free software: you can redistribute it and/or modify
   4 ;;  it under the terms of the GNU General Public License as published by
   5 ;;  the Free Software Foundation, either version 3 of the License, or
   6 ;;  (at your option) any later version.
   7
   8 ;;  This file is distributed in the hope that it will be useful,
   9 ;;  but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 ;;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 ;;  GNU General Public License for more details.
  12
  13 ;;  You should have received a copy of the GNU General Public License
  14 ;;  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 (import (readline) (reader) (printer))
  17
  18 (define (READ str)
  19   (read_str str))
  20
  21 (define (EVAL ast env) ast)
  22
  23 (define (PRINT exp)
  24   (and (not (eof-object? exp))
  25        (format #t "~a~%" (pr_str exp #t))))
  26
  27 (define (LOOP continue?)
  28   (and continue? (REPL)))
  29
  30 (define (REPL)
  31   (LOOP
  32    (let ((line (_readline "user> ")))
  33      (cond
  34        ((eof-object? line) #f)
  35        ((string=? line "") #t)
  36        (else
  37          (catch 'mal-error
  38                 (lambda () (PRINT (EVAL (READ line) '())))
  39                 (lambda (k . e)
  40                   (format #t "Error: ~a~%" (pr_str (car e) #t)))))))))
  41
  42 (REPL)