;;; -*-scheme-*-

;;; Mes --- Maxwell Equations of Software
;;; Copyright © 2016,2017 Jan Nieuwenhuizen <janneke@gnu.org>
;;;
;;; This file is part of Mes.
;;;
;;; Mes 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 3 of the License, or (at
;;; your option) any later version.
;;;
;;; Mes 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 Mes.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

(define-macro (define-module module . rest) #t)
(define-macro (use-modules . rest) #t)
(define-macro (cond-expand-provide . rest) #t)

(define-macro (include-from-path file)
  (let loop ((path (cons %moduledir (string-split (or (getenv "GUILE_LOAD_PATH") "") #\:))))
    (if (getenv "MES_DEBUG") (format (current-error-port) "include-from-path: ~s [PATH:~s]\n" file path))
    (if (null? path) (error "include-from-path: not found: " file)
        (let ((file (string-append (car path) "/" file)))
          (if (access? file R_OK) `(load ,file)
              (loop (cdr path)))))))

(mes-use-module (srfi srfi-16))

(define (drain-input port)
  (list->string
   (let loop ((c (read-char)))
     (if (eq? c #\*eof*) '()
         (cons c (loop (read-char)))))))

(define (make-string n . fill)
  (list->string (apply make-list n fill)))

(define (object->string x . rest)
  (with-output-to-string
    (lambda () ((if (pair? rest) (car rest) write) x))))

(define (port-filename p) "<stdin>")
(define (port-line p) 0)
(define (simple-format port format . rest) (map (lambda (x) (display x port)) rest))

(define (with-input-from-string string thunk)
  (define save-peek-char peek-char)
  (define save-read-char read-char)
  (define save-unread-char unread-char)
  (let ((tell 0)
        (end (string-length string)))
    (set! peek-char
          (lambda () (if (= tell end) (integer->char -1)
                         (string-ref string (- tell 1)))))
    (set! read-char
          (lambda () (if (= tell end) (integer->char -1)
                         (begin
                           (set! tell (1+ tell))
                           (string-ref string (- tell 1))))))
    (set! unread-char
          (lambda (c) (set! tell (1- tell)) c)))
  (let ((r (thunk)))
    (set! peek-char save-peek-char)
    (set! read-char save-read-char)
    (set! unread-char save-unread-char)
    r))

(define (with-input-from-file file thunk)
  (let ((port (open-input-file file)))
    (if (= port -1)
        (error 'no-such-file file)
        (let* ((save (current-input-port))
               (foo (set-current-input-port port))
               (r (thunk)))
          (set-current-input-port save)
          r))))

(define (with-output-to-file file thunk)
  (let ((port (open-output-file file)))
    (if (= port -1)
        (error 'cannot-open file)
        (let* ((save (current-output-port))
               (foo (set-current-output-port port))
               (r (thunk)))
          (set-current-output-port save)
          r))))

(define (with-output-to-port port thunk)
  (let* ((save (current-output-port))
         (foo (set-current-output-port port))
         (r (thunk)))
    (set-current-output-port save)
    r))

(define open-input-string
  (let ((save-set-current-input-port #f)
        (string-port #f))
    (lambda (string)
      (set! save-set-current-input-port set-current-input-port)
      (set! string-port (cons '*string-port* (gensym)))
      (set! set-current-input-port
            (let ((save-peek-char peek-char)
                  (save-read-char read-char)
                  (save-unread-char unread-char)
                  (tell 0)
                  (end (string-length string)))
              (lambda (port)
                (if (not (equal? port string-port)) (save-set-current-input-port port)
                    (begin
                      (set! peek-char
                            (lambda () (if (= tell end) (integer->char -1)
                                           (string-ref string (- tell 1)))))
                      (set! read-char
                            (lambda () (if (= tell end) (integer->char -1)
                                           (begin
                                             (set! tell (1+ tell))
                                             (string-ref string (- tell 1))))))
                      (set! unread-char
                            (lambda (c) (set! tell (1- tell)) c))
                      (set! set-current-input-port
                            (lambda (port)
                              (save-set-current-input-port port)
                              (set! peek-char save-peek-char)
                              (set! read-char save-read-char)
                              (set! unread-char save-unread-char)
                              (set! set-current-input-port save-set-current-input-port)
                              string-port)))))))
      string-port)))

(define (read-string)
  (define (read-string c p s)
    (if (eq? c #\*eof*) s
        (read-string (read-char) (peek-char) (cons c s))))
  (list->string (reverse (read-string (read-char) (peek-char) (list)))))