clic/3rdparties/software/babel-20200218-git/src/sharp-backslash.lisp

3rdparties/software/babel-20200218-git/src/sharp-backslash.lisp (3620 bytes)
1 ;;;; -*- Mode: lisp; indent-tabs-mode: nil -*-
2 ;;;
3 ;;; sharp-backslash.lisp --- Alternative #\ dispatch code.
4 ;;;
5 ;;; Copyright (C) 2007-2009, Luis Oliveira  <loliveira@common-lisp.net>
6 ;;;
7 ;;; Permission is hereby granted, free of charge, to any person
8 ;;; obtaining a copy of this software and associated documentation
9 ;;; files (the "Software"), to deal in the Software without
10 ;;; restriction, including without limitation the rights to use, copy,
11 ;;; modify, merge, publish, distribute, sublicense, and/or sell copies
12 ;;; of the Software, and to permit persons to whom the Software is
13 ;;; furnished to do so, subject to the following conditions:
14 ;;;
15 ;;; The above copyright notice and this permission notice shall be
16 ;;; included in all copies or substantial portions of the Software.
17 ;;;
18 ;;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19 ;;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 ;;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21 ;;; NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
22 ;;; HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
23 ;;; WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 ;;; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
25 ;;; DEALINGS IN THE SOFTWARE.
26 
27 (in-package #:babel)
28 
29 #-allegro
30 (defun sharp-backslash-reader (original-reader stream char numarg)
31   (let ((1st-char (read-char stream)))
32     (if (and (char-equal 1st-char #\u)
33              ;; because #\z is not a digit char...
34              (digit-char-p (peek-char nil stream nil #\z) 16))
35         ;; something better than READ would be nice here
36         (let ((token (let ((*read-base* 16)) (read stream))))
37           (if (typep token 'babel-encodings::code-point)
38               (code-char token)
39               (if *read-suppress*
40                   nil
41                   (simple-reader-error
42                    stream "Unrecognized character name: u~A" token))))
43         (funcall original-reader
44                  (make-concatenated-stream (make-string-input-stream
45                                             (string 1st-char))
46                                            stream)
47                  char
48                  numarg))))
49 
50 ;;; Allegro's PEEK-CHAR seems broken in some situations, and the code
51 ;;; above would generate an error about too many calls to UNREAD-CHAR.
52 ;;; Then Allegro's original SHARP-BACKSLASH wants to UNREAD-CHAR
53 ;;; twice, very weird.  This is the best workaround I could think of.
54 ;;; It sucks.
55 #+allegro
56 (defun sharp-backslash-reader (original-reader stream char numarg)
57   (let* ((1st-char (read-char stream))
58          (rest (ignore-errors (excl::read-extended-token stream)))
59          (code (when (and rest (char-equal 1st-char #\u))
60                  (ignore-errors (parse-integer rest :radix 16)))))
61     (if code
62         (code-char code)
63         (with-input-from-string
64             (s (concatenate 'string "#\\" (string 1st-char) rest))
65           (read-char s)
66           (read-char s)
67           (funcall original-reader s char numarg)))))
68 
69 (defun make-sharp-backslash-reader ()
70   (let ((original-sharp-backslash (get-dispatch-macro-character #\# #\\)))
71     (lambda (stream char numarg)
72       (sharp-backslash-reader original-sharp-backslash stream char numarg))))
73 
74 (defmacro enable-sharp-backslash-syntax ()
75   `(eval-when (:compile-toplevel :execute)
76      (setf *readtable* (copy-readtable *readtable*))
77      (set-sharp-backslash-syntax-in-readtable)
78      (values)))
79 
80 (defun set-sharp-backslash-syntax-in-readtable ()
81   (set-dispatch-macro-character #\# #\\ (make-sharp-backslash-reader))
82   (values))