mes/module/mes/display.mes

;;; -*-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:

(mes-use-module (mes scm))
;;(mes-use-module (mes srfi srfi-1))

(define (srfi-1:member x lst eq)
  (if (null? lst) #f
      (if (eq x (car lst)) lst
          (srfi-1:member x (cdr lst) eq))))

(define (next-xassq x a)
  (and=> (srfi-1:member x a (lambda (x e) (eq? x (cdr e))))
         (lambda (a) (xassq x (cdr a)))))

(define (next-xassq2 x a)
  (and=> (srfi-1:member x a (lambda (x e) (eq? x (cdr e))))
         (lambda (a)
           (and=> (srfi-1:member x (cdr a) (lambda (x e) (eq? x (cdr e))))
                  (lambda (a) (xassq x (cdr a)))))))

(define (display x . rest)
  (let* ((port (if (null? rest) (current-output-port) (car rest)))
         (write? (and (pair? rest) (pair? (cdr rest)) (cadr rest))))

    (define-macro (cut f slot n1)
      `(lambda (slot) (,f slot ,n1)))

    (define-macro (cut2 f slot n1 n2)
      `(lambda (slot) (,f slot ,n1 ,n2)))

    (define (display-char x port write?)
      (cond ((and write? (or (eq? x #\") (eq? x #\\)))
             (write-char #\\ port)
             (write-char x port))
            ((and write? (eq? x #\newline))
             (write-char #\\ port)
             (write-char #\n port))
            (#t (write-char x port))))

    (define (d x cont? sep)
      (for-each (cut write-char <> port) (string->list sep))
      (cond
       ((char? x)
        (if (not write?) (write-char x port)
            (let ((name (and=> (assq x '((#\*eof* . *eof*)
                                         (#\nul . nul)
                                         (#\alarm . alarm)
                                         (#\backspace . backspace)
                                         (#\tab . tab)
                                         (#\newline . newline)
                                         (#\vtab . vtab)
                                         (#\page . page)
                                         (#\return . return)
                                         (#\space . space)))
                               cdr)))
              (write-char #\# port)
              (write-char #\\ port)
              (if name (display name port)
                  (write-char x port)))))
       ((closure? x)
        (display "#<procedure " port)
        (let ((name (and=> (next-xassq2 x (current-module)) car)))
          (display name port))
        (display " " port)
        (display (cadr (core:cdr x)) port)
        (display ">" port))
       ((continuation? x)
        (display "#<continuation " port)
        (display (core:car x) port)
        (display ">" port))
       ((macro? x)
        (display "#<macro " port)
        (display (core:cdr x) port)
        (display ">" port))
       ((number? x)
        (display (number->string x) port))
       ((pair? x)
        (if (not cont?) (write-char #\( port))
        (cond ((eq? (car x) '*circular*)
               (display "(*circ* . #-1#)" port))
              ((eq? (car x) '*closure*)
               (display "(*closure* . #-1#)" port))
              (#t
               (display (car x) port write?)
               (if (pair? (cdr x)) (d (cdr x) #t " ")
                   (if (and (cdr x) (not (null? (cdr x))))
                       (begin
                         (display " . " port)
                         (display (cdr x) port write?))))
               (if (not cont?) (write-char #\) port)))))
       ((or (keyword? x) (special? x) (string? x) (symbol? x))
        (if (and (string? x) write?) (write-char #\" port))
        (if (keyword? x) (display "#:" port))
        (for-each (cut2 display-char <> port write?) (string->list x))
        (if (and (string? x) write?) (write-char #\" port)))
       ((vector? x)
        (display "#(" port)
        (for-each (lambda (i)
                    (let ((x (vector-ref x i)))
                      (if (vector? x)
                          (begin
                            (display (if (= i 0) "" " ") port)
                            (display "#(...)" port))
                          (d x #f (if (= i 0) "" " ")))))
                  (iota (vector-length x)))
        (display ")" port))
       ((function? x)
        (display "#<procedure " port)
        (display (core:car x) port)
        (display " " port)
        (display
         (case (core:arity x)
           ((-1) "_")
           ((0) "()")
           ((1) "(_)")
           ((2) "(_ _)")
           ((3) "(_ _ _)"))
         port)
        (display ">" port))
       ((broken-heart? x)
        (display "<3" port))
       (#t
        (display "TODO type=") (display (cell:type-name x)) (newline)))
      *unspecified*)
    (d x #f "")))

(define (write-char x . rest)
  (apply write-byte (cons (char->integer x) rest)))

(define (write x . rest)
  (let ((port (if (null? rest) (current-output-port) (car rest))))
    (display x port #t)))

(define (newline . rest)
  (apply display (cons "\n" rest)))

(define (with-output-to-string thunk)
  (define save-write-byte write-byte)
  (let ((stdout '()))
    (set! write-byte
          (lambda (x . rest)
            (let ((out? (or (null? rest) (eq? (car rest) (current-output-port)))))
              (if (not out?) (apply save-write-byte (cons x rest))
                  (begin
                    (set! stdout (append stdout (list (integer->char x))))
                    x)))))
    (thunk)
    (let ((r (apply string stdout)))
      (set! write-byte save-write-byte)
      r)))

(define (simple-format destination format . rest)
  (let ((port (if (boolean? destination) (current-output-port) destination))
        (lst (string->list format)))
    (define (simple-format lst args)
      (if (pair? lst)
          (let ((c (car lst)))
            (if (not (eq? c #\~)) (begin (write-char (car lst) port)
                                         (simple-format (cdr lst) args))
                (let ((c (cadr lst)))
                  (case c
                    ((#\a) (display (car args) port))
                    ((#\s) (write (car args) port)))
                  (simple-format (cddr lst) (cdr args)))))))
    
    (if destination (simple-format lst rest)
        (with-output-to-string
          (lambda () (simple-format lst rest))))))
(define format simple-format)