Implement #\x... syntax for characters.

diff --git a/src/runtime/char.scm b/src/runtime/char.scm
index 18772031ea02217193be56c10d5fc79dcdfd14e3..3d89aa3b2c0575b1c7aed3a4450cbbf355e28c5b 100644 (file)
--- a/src/runtime/char.scm
+++ b/src/runtime/char.scm
@@ -235,7 +235,11 @@ USA.
                 (loop (fix:+ hyphen 1) (fix:or bit bits)))
               (make-char
                (or (->code named-codes string start end)
-                   (and (substring-prefix-ci? "U+" 0 1 string start end)
+                   ;; R7RS syntax:
+                   (and (substring-prefix-ci? "x" 0 1 string start end)
+                        (substring->number string (fix:+ start 1) end 16))
+                   ;; Non-standard Unicode-style syntax:
+                   (and (substring-prefix-ci? "u+" 0 2 string start end)
                         (substring->number string (fix:+ start 2) end 16))
                    (lose))
                bits))))))))
@@ -255,15 +259,7 @@ USA.
             ((char-graphic? base-char)
              (string base-char))
             (else
-             (string-append "U+"
-                            (let ((s (number->string code 16)))
-                              (string-pad-left s
-                                               (let ((l (string-length s)))
-                                                 (let loop ((n 2))
-                                                   (if (fix:<= l n)
-                                                       n
-                                                       (loop (fix:* 2 n)))))
-                                               #\0)))))))))
+             (string-append "x" (number->string code 16))))))))
 
 ;; This procedure used by Edwin.
 (define (bucky-bits->prefix bits)