Don't downcase system diagnostics' first letters

[gnu-emacs] / lisp / international / mule.el

diff --git a/lisp/international/mule.el b/lisp/international/mule.el
index 47c7087518e7989f181f7c419d075b04c42378f1..181474c65ce8c10920a791f8d3ad0f2dfeffe48e 100644 (file)
--- a/lisp/international/mule.el
+++ b/lisp/international/mule.el
@@ -1,6 +1,6 @@
 ;;; mule.el --- basic commands for multilingual environment
 
 ;;; mule.el --- basic commands for multilingual environment
 

-;; Copyright (C) 1997-2013 Free Software Foundation, Inc.
+;; Copyright (C) 1997-2015 Free Software Foundation, Inc.

 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
 ;;   2005, 2006, 2007, 2008, 2009, 2010, 2011
 ;;   National Institute of Advanced Industrial Science and Technology (AIST)
 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
 ;;   2005, 2006, 2007, 2008, 2009, 2010, 2011
 ;;   National Institute of Advanced Industrial Science and Technology (AIST)


@@ -407,12 +407,12 @@ PLIST (property list) may contain any type of information a user
 ;; because that makes a bootstrapping problem
 ;; if you need to recompile all the Lisp files using interpreted code.
 
 ;; because that makes a bootstrapping problem
 ;; if you need to recompile all the Lisp files using interpreted code.
 

-(defun charset-id (charset)
+(defun charset-id (_charset)

   "Always return 0.  This is provided for backward compatibility."
   (declare (obsolete nil "23.1"))
   0)
 
   "Always return 0.  This is provided for backward compatibility."
   (declare (obsolete nil "23.1"))
   0)
 

-(defmacro charset-bytes (charset)
+(defmacro charset-bytes (_charset)

   "Always return 0.  This is provided for backward compatibility."
   (declare (obsolete nil "23.1"))
   0)
   "Always return 0.  This is provided for backward compatibility."
   (declare (obsolete nil "23.1"))
   0)


@@ -471,7 +471,7 @@ Return -1 if charset isn't an ISO 2022 one."
 ;;; CHARACTER
 (define-obsolete-function-alias 'char-valid-p 'characterp "23.1")
 
 ;;; CHARACTER
 (define-obsolete-function-alias 'char-valid-p 'characterp "23.1")
 

-(defun generic-char-p (char)
+(defun generic-char-p (_char)

   "Always return nil.  This is provided for backward compatibility."
   (declare (obsolete nil "23.1"))
   nil)
   "Always return nil.  This is provided for backward compatibility."
   (declare (obsolete nil "23.1"))
   nil)


@@ -518,7 +518,8 @@ Return -1 if charset isn't an ISO 2022 one."
     composition
     euc-tw-shift
     use-roman
     composition
     euc-tw-shift
     use-roman

-    use-oldjis)
+    use-oldjis
+    8-bit-level-4)

   "List of symbols that control ISO-2022 encoder/decoder.
 
 The value of the `:flags' attribute in the argument of the function
   "List of symbols that control ISO-2022 encoder/decoder.
 
 The value of the `:flags' attribute in the argument of the function


@@ -542,8 +543,9 @@ If `locking-shift' is specified, decode locking-shift code correctly
 on decoding, and use locking-shift to invoke a graphic element on
 encoding.
 
 on decoding, and use locking-shift to invoke a graphic element on
 encoding.
 

-If `single-shift' is specified, decode single-shift code correctly on
-decoding, and use single-shift to invoke a graphic element on encoding.
+If `single-shift' is specified, decode single-shift code
+correctly on decoding, and use single-shift to invoke a graphic
+element on encoding.  See also `8-bit-level-4' specification.

 
 If `designation' is specified, decode designation code correctly on
 decoding, and use designation to designate a charset to a graphic
 
 If `designation' is specified, decode designation code correctly on
 decoding, and use designation to designate a charset to a graphic


@@ -578,13 +580,42 @@ If `use-roman' is specified, JIS0201-1976-Roman is designated instead
 of ASCII.
 
 If `use-oldjis' is specified, JIS0208-1976 is designated instead of
 of ASCII.
 
 If `use-oldjis' is specified, JIS0208-1976 is designated instead of

-JIS0208-1983.")
+JIS0208-1983.
+
+If `8-bit-level-4' is specified, the decoder assumes the
+implementation level \"4\" for 8-bit codes which means that GL is
+identified as the single-shift area.  The default implementation
+level for 8-bit code is \"4A\" which means that GR is identified
+as the single-shift area.")

 
 (defun define-coding-system (name docstring &rest props)
   "Define NAME (a symbol) as a coding system with DOCSTRING and attributes.
 The remaining arguments must come in pairs ATTRIBUTE VALUE.  ATTRIBUTE
 may be any symbol.
 
 
 (defun define-coding-system (name docstring &rest props)
   "Define NAME (a symbol) as a coding system with DOCSTRING and attributes.
 The remaining arguments must come in pairs ATTRIBUTE VALUE.  ATTRIBUTE
 may be any symbol.
 

+A coding system specifies a rule to decode (i.e. to convert a
+byte sequence to a character sequence) and a rule to encode (the
+opposite of decoding).
+
+The decoding is done by at most 3 steps; the first is to convert
+a byte sequence to a character sequence by one of Emacs'
+internal routines specified by `:coding-type' attribute.  The
+optional second step is to convert the character sequence (the
+result of the first step) by a translation table specified
+by `:decode-translation-table' attribute.  The optional third step
+is to convert the above result by a Lisp function specified
+by `:post-read-conversion' attribute.
+
+The encoding is done by at most 3 steps, which are the reverse
+of the decoding steps.  The optional first step converts a
+character sequence to another character sequence by a Lisp
+function specified by `:pre-write-conversion' attribute.  The
+optional second step converts the above result by a translation
+table specified by `:encode-translation-table' attribute.  The
+third step converts the above result to a byte sequence by one
+of the Emacs's internal routines specified by the `:coding-type'
+attribute.
+

 The following attributes have special meanings.  Those labeled as
 \"(required)\" should not be omitted.
 
 The following attributes have special meanings.  Those labeled as
 \"(required)\" should not be omitted.
 


@@ -594,27 +625,72 @@ VALUE is a character to display on mode line for the coding system.
 
 `:coding-type' (required)
 
 
 `:coding-type' (required)
 

-VALUE must be one of `charset', `utf-8', `utf-16', `iso-2022',
-`emacs-mule', `shift-jis', `ccl', `raw-text', `undecided'.
+VALUE specifies the format of byte sequence the coding system
+decodes and encodes to.  It must be one of `charset', `utf-8',
+`utf-16', `iso-2022', `emacs-mule', `shift-jis', `ccl',
+`raw-text', `undecided'.
+
+If VALUE is `charset', the coding system is for handling a
+byte sequence in which each byte or every two- to four-byte
+sequence represents a character code of a charset specified
+by the `:charset-list' attribute.
+
+If VALUE is `utf-8', the coding system is for handling Unicode
+UTF-8 byte sequences.  See also the documentation of the
+attribute `:bom'.
+
+If VALUE is `utf-16', the coding system is for handling Unicode
+UTF-16 byte sequences.  See also the documentation of the
+attributes :bom and `:endian'.
+
+If VALUE is `iso-2022', the coding system is for handling byte
+sequences conforming to ISO/IEC 2022.  See also the documentation
+of the attributes `:charset-list', `:flags', and `:designation'.
+
+If VALUE is `emacs-mule', the coding system is for handling
+byte sequences which Emacs 20 and 21 used for their internal
+representation of characters.
+
+If VALUE is `shift-jis', the coding system is for handling byte
+sequences of Shift_JIS format.  See also the attribute `:charset-list'.
+
+If VALUE is `ccl', the coding system uses CCL programs to decode
+and encode byte sequences.  The CCL programs must be
+specified by the attributes `:ccl-decoder' and `:ccl-encoder'.
+
+If VALUE is `raw-text', the coding system decodes byte sequences
+without any conversions.

 
 `:eol-type'
 
 VALUE is the EOL (end-of-line) format of the coding system.  It must be
 one of `unix', `dos', `mac'.  The symbol `unix' means Unix-like EOL
 
 `:eol-type'
 
 VALUE is the EOL (end-of-line) format of the coding system.  It must be
 one of `unix', `dos', `mac'.  The symbol `unix' means Unix-like EOL

-\(i.e. single LF), `dos' means DOS-like EOL \(i.e. sequence of CR LF),
-and `mac' means Mac-like EOL \(i.e. single CR).  If omitted, Emacs
-detects the EOL format automatically when decoding.
+\(i.e. a single LF character), `dos' means DOS-like EOL \(i.e. a sequence
+of CR followed by LF), and `mac' means Mac-like EOL \(i.e. a single CR).
+If omitted, Emacs detects the EOL format automatically when decoding.
+
+`:charset-list' (required if `:coding-type' is `charset' or `shift-jis')
+
+VALUE must be a list of charsets supported by the coding system.

 
 

-`:charset-list'
+If `coding-type:' is `charset', then on decoding and encoding by the
+coding system, if a character belongs to multiple charsets in the
+list, a charset that comes first in the list is selected.

 
 

-VALUE must be a list of charsets supported by the coding system.  On
-encoding by the coding system, if a character belongs to multiple
-charsets in the list, a charset that comes earlier in the list is
-selected.  If `:coding-type' is `iso-2022', VALUE may be `iso-2022',
-which indicates that the coding system supports all ISO-2022 based
-charsets.  If `:coding-type' is `emacs-mule', VALUE may be
-`emacs-mule', which indicates that the coding system supports all
-charsets that have the `:emacs-mule-id' property.
+If `:coding-type' is `iso-2022', VALUE may be `iso-2022', which
+indicates that the coding system supports all ISO-2022 based
+charsets.
+
+If `:coding-type' is `shift-jis', VALUE must be a list of three
+to four charsets supported by Shift_JIS encoding scheme.  The
+first charset (one dimension) is for code space 0x00..0x7F, the
+second (one dimension) for 0xA1..0xDF, the third (two dimension)
+for 0x8140..0xEFFC, the optional fourth (three dimension) for
+0xF040..0xFCFC.
+
+If `:coding-type' is `emacs-mule', VALUE may be `emacs-mule',
+which indicates that the coding system supports all charsets that
+have the `:emacs-mule-id' property.

 
 `:ascii-compatible-p'
 
 
 `:ascii-compatible-p'
 


@@ -635,9 +711,9 @@ VALUE must be a translation table to use on encoding.
 VALUE must be a function to call after some text is inserted and
 decoded by the coding system itself and before any functions in
 `after-insert-functions' are called.  This function is passed one
 VALUE must be a function to call after some text is inserted and
 decoded by the coding system itself and before any functions in
 `after-insert-functions' are called.  This function is passed one

-argument; the number of characters in the text to convert, with
+argument: the number of characters in the text to convert, with

 point at the start of the text.  The function should leave point
 point at the start of the text.  The function should leave point

-the same, and return the new character count.
+unchanged, and should return the new character count.

 
 `:pre-write-conversion'
 
 
 `:pre-write-conversion'
 


@@ -666,13 +742,13 @@ to lower case.
 `:mime-text-unsuitable'
 
 VALUE non-nil means the `:mime-charset' property names a charset which
 `:mime-text-unsuitable'
 
 VALUE non-nil means the `:mime-charset' property names a charset which

-is unsuitable for the top-level media type \"text\".
+is unsuitable for the top-level media of type \"text\".

 
 `:flags'
 
 VALUE must be a list of symbols that control the ISO-2022 converter.
 Each must be a member of the list `coding-system-iso-2022-flags'
 
 `:flags'
 
 VALUE must be a list of symbols that control the ISO-2022 converter.
 Each must be a member of the list `coding-system-iso-2022-flags'

-\(which see).  This attribute has a meaning only when `:coding-type'
+\(which see).  This attribute is meaningful only when `:coding-type'

 is `iso-2022'.
 
 `:designation'
 is `iso-2022'.
 
 `:designation'


@@ -692,12 +768,12 @@ to GN.  If the list contains 96, any charsets whose whose ranges are
 96 long can be designated to GN.  If the first element is a charset,
 that charset is initially designated to GN.
 
 96 long can be designated to GN.  If the first element is a charset,
 that charset is initially designated to GN.
 

-This attribute has a meaning only when `:coding-type' is `iso-2022'.
+This attribute is meaningful only when `:coding-type' is `iso-2022'.

 
 `:bom'
 
 
 `:bom'
 

-This attributes specifies whether the coding system uses a `byte order
-mark'.  VALUE must be nil, t, or cons of coding systems whose
+This attributes specifies whether the coding system uses a \"byte order
+mark\".  VALUE must be nil, t, or a cons cell of coding systems whose

 `:coding-type' is `utf-16' or `utf-8'.
 
 If the value is nil, on decoding, don't treat the first two-byte as
 `:coding-type' is `utf-16' or `utf-8'.
 
 If the value is nil, on decoding, don't treat the first two-byte as


@@ -706,13 +782,13 @@ BOM, and on encoding, don't produce BOM bytes.
 If the value is t, on decoding, skip the first two-byte as BOM, and on
 encoding, produce BOM bytes according to the value of `:endian'.
 
 If the value is t, on decoding, skip the first two-byte as BOM, and on
 encoding, produce BOM bytes according to the value of `:endian'.
 

-If the value is cons, on decoding, check the first two-byte.  If they
-are 0xFE 0xFF, use the car part coding system of the value.  If they
-are 0xFF 0xFE, use the cdr part coding system of the value.
+If the value is a cons cell, on decoding, check the first two bytes.
+If they are 0xFE 0xFF, use the car part coding system of the value.
+If they are 0xFF 0xFE, use the cdr part coding system of the value.

 Otherwise, treat them as bytes for a normal character.  On encoding,
 produce BOM bytes according to the value of `:endian'.
 
 Otherwise, treat them as bytes for a normal character.  On encoding,
 produce BOM bytes according to the value of `:endian'.
 

-This attribute has a meaning only when `:coding-type' is `utf-16' or
+This attribute is meaningful only when `:coding-type' is `utf-16' or

 `utf-8'.
 
 `:endian'
 `utf-8'.
 
 `:endian'


@@ -720,19 +796,38 @@ This attribute has a meaning only when `:coding-type' is `utf-16' or
 VALUE must be `big' or `little' specifying big-endian and
 little-endian respectively.  The default value is `big'.
 
 VALUE must be `big' or `little' specifying big-endian and
 little-endian respectively.  The default value is `big'.
 

-This attribute has a meaning only when `:coding-type' is `utf-16'.
+This attribute is meaningful only when `:coding-type' is `utf-16'.
+
+`:ccl-decoder' (required if :coding-type is `ccl')
+
+VALUE is a CCL program name defined by `define-ccl-program'.  The
+CCL program reads a byte sequence and writes a character sequence
+as a decoding result.
+
+`:ccl-encoder' (required if :coding-type is `ccl')
+
+VALUE is a CCL program name defined by `define-ccl-program'.  The
+CCL program reads a character sequence and writes a byte sequence
+as an encoding result.

 
 

-`:ccl-decoder'
+`:inhibit-null-byte-detection'

 
 

-VALUE is a symbol representing the registered CCL program used for
-decoding.  This attribute has a meaning only when `:coding-type' is
-`ccl'.
+VALUE non-nil means Emacs ignore null bytes on code detection.
+See the variable `inhibit-null-byte-detection'.  This attribute
+is meaningful only when `:coding-type' is `undecided'.

 
 

-`:ccl-encoder'
+`:inhibit-iso-escape-detection'

 
 

-VALUE is a symbol representing the registered CCL program used for
-encoding.  This attribute has a meaning only when `:coding-type' is
-`ccl'."
+VALUE non-nil means Emacs ignores ISO-2022 escape sequences on
+code detection.  See the variable `inhibit-iso-escape-detection'.
+This attribute is meaningful only when `:coding-type' is
+`undecided'.
+
+`:prefer-utf-8'
+
+VALUE non-nil means Emacs prefers UTF-8 on code detection for
+non-ASCII files.  This attribute is meaningful only when
+`:coding-type' is `undecided'."

   (let* ((common-attrs (mapcar 'list
                               '(:mnemonic
                                 :coding-type
   (let* ((common-attrs (mapcar 'list
                               '(:mnemonic
                                 :coding-type


@@ -761,7 +856,11 @@ encoding.  This attribute has a meaning only when `:coding-type' is
                                   ((eq coding-type 'ccl)
                                    '(:ccl-decoder
                                      :ccl-encoder
                                   ((eq coding-type 'ccl)
                                    '(:ccl-decoder
                                      :ccl-encoder

-                                     :valids))))))
+                                     :valids))
+                                  ((eq coding-type 'undecided)
+                                   '(:inhibit-null-byte-detection
+                                     :inhibit-iso-escape-detection
+                                     :prefer-utf-8))))))

 
     (dolist (slot common-attrs)
       (setcdr slot (plist-get props (car slot))))
 
     (dolist (slot common-attrs)
       (setcdr slot (plist-get props (car slot))))


@@ -1236,7 +1335,9 @@ just set the variable `buffer-file-coding-system' directly."
   (if (and coding-system buffer-file-coding-system (null force))
       (setq coding-system
            (merge-coding-systems coding-system buffer-file-coding-system)))
   (if (and coding-system buffer-file-coding-system (null force))
       (setq coding-system
            (merge-coding-systems coding-system buffer-file-coding-system)))

-  (when (called-interactively-p 'interactive)
+  (when (and (called-interactively-p 'interactive)
+            (not (memq 'emacs (coding-system-get coding-system
+                                                 :charset-list))))

     ;; Check whether save would succeed, and jump to the offending char(s)
     ;; if not.
     (let ((css (find-coding-systems-region (point-min) (point-max))))
     ;; Check whether save would succeed, and jump to the offending char(s)
     ;; if not.
     (let ((css (find-coding-systems-region (point-min) (point-max))))


@@ -1313,7 +1414,7 @@ graphical terminals."
   (if coding-system
       (setq default-terminal-coding-system coding-system))
   (set-terminal-coding-system-internal coding-system terminal)
   (if coding-system
       (setq default-terminal-coding-system coding-system))
   (set-terminal-coding-system-internal coding-system terminal)

-  (redraw-frame (selected-frame)))
+  (redraw-frame))

 
 (defvar default-keyboard-coding-system nil
   "Default value of the keyboard coding system.
 
 (defvar default-keyboard-coding-system nil
   "Default value of the keyboard coding system.


@@ -1396,7 +1497,7 @@ use either \\[customize] or \\[set-keyboard-coding-system]."
   :type '(coding-system :tag "Coding system")
   :link '(info-link "(emacs)Terminal Coding")
   :link '(info-link "(emacs)Unibyte Mode")
   :type '(coding-system :tag "Coding system")
   :link '(info-link "(emacs)Terminal Coding")
   :link '(info-link "(emacs)Unibyte Mode")

-  :set (lambda (symbol value)
+  :set (lambda (_symbol value)

         ;; Don't load encoded-kb unnecessarily.
         (if (or value (boundp 'encoded-kbd-setup-display))
             (set-keyboard-coding-system value)
         ;; Don't load encoded-kb unnecessarily.
         (if (or value (boundp 'encoded-kbd-setup-display))
             (set-keyboard-coding-system value)


@@ -1691,7 +1792,7 @@ ARC\\|ZIP\\|LZH\\|LHA\\|ZOO\\|[JEW]AR\\|XPI\\|RAR\\|7Z\\)\\'"
     ("\\.\\(gz\\|Z\\|bz\\|bz2\\|xz\\|gpg\\)\\'" . no-conversion)
     ("\\.\\(jpe?g\\|png\\|gif\\|tiff?\\|p[bpgn]m\\)\\'" . no-conversion)
     ("\\.pdf\\'" . no-conversion)
     ("\\.\\(gz\\|Z\\|bz\\|bz2\\|xz\\|gpg\\)\\'" . no-conversion)
     ("\\.\\(jpe?g\\|png\\|gif\\|tiff?\\|p[bpgn]m\\)\\'" . no-conversion)
     ("\\.pdf\\'" . no-conversion)

-    ("/#[^/]+#\\'" . emacs-mule)))
+    ("/#[^/]+#\\'" . utf-8-emacs-unix)))

   "Alist of filename patterns vs corresponding coding systems.
 Each element looks like (REGEXP . CODING-SYSTEM).
 A file whose name matches REGEXP is decoded by CODING-SYSTEM on reading.
   "Alist of filename patterns vs corresponding coding systems.
 Each element looks like (REGEXP . CODING-SYSTEM).
 A file whose name matches REGEXP is decoded by CODING-SYSTEM on reading.


@@ -1817,7 +1918,7 @@ If nothing is specified, the return value is nil."
             (head-end (+ head-start (min size 1024)))
             (tail-start (+ head-start (max (- size 3072) 0)))
             (tail-end (+ head-start size))
             (head-end (+ head-start (min size 1024)))
             (tail-start (+ head-start (max (- size 3072) 0)))
             (tail-end (+ head-start size))

-            coding-system head-found tail-found pos char-trans)
+            coding-system head-found tail-found char-trans)

        ;; Try a short cut by searching for the string "coding:"
        ;; and for "unibyte:" at the head and tail of SIZE bytes.
        (setq head-found (or (search-forward "coding:" head-end t)
        ;; Try a short cut by searching for the string "coding:"
        ;; and for "unibyte:" at the head and tail of SIZE bytes.
        (setq head-found (or (search-forward "coding:" head-end t)


@@ -1844,8 +1945,11 @@ If nothing is specified, the return value is nil."
                       (re-search-forward
                        "\\(.*;\\)?[ \t]*unibyte:[ \t]*\\([^ ;]+\\)"
                        head-end t))
                       (re-search-forward
                        "\\(.*;\\)?[ \t]*unibyte:[ \t]*\\([^ ;]+\\)"
                        head-end t))

-              (display-warning 'mule "`unibyte: t' is obsolete; \
-use \"coding: 'raw-text\" instead." :warning)
+              (display-warning 'mule
+                               (format "\"unibyte: t\" (in %s) is obsolete; \
+use \"coding: 'raw-text\" instead."
+                                       (file-relative-name filename))
+                               :warning)

              (setq coding-system 'raw-text))
            (when (and (not coding-system)
                       (re-search-forward
              (setq coding-system 'raw-text))
            (when (and (not coding-system)
                       (re-search-forward


@@ -1924,11 +2028,10 @@ use \"coding: 'raw-text\" instead." :warning)
       (let ((funcs auto-coding-functions)
            (coding-system nil))
        (while (and funcs (not coding-system))
       (let ((funcs auto-coding-functions)
            (coding-system nil))
        (while (and funcs (not coding-system))

-         (setq coding-system (condition-case e
-                                 (save-excursion
-                                   (goto-char (point-min))
-                                   (funcall (pop funcs) size))
-                               (error nil))))
+         (setq coding-system (ignore-errors
+                               (save-excursion
+                                 (goto-char (point-min))
+                                 (funcall (pop funcs) size)))))

        (if coding-system
            (cons coding-system 'auto-coding-functions)))))
 
        (if coding-system
            (cons coding-system 'auto-coding-functions)))))
 


@@ -2214,7 +2317,13 @@ ALIST is an alist, each element has the form (FROM . TO).
 FROM and TO are a character or a vector of characters.
 If FROM is a character, that character is translated to TO.
 If FROM is a vector of characters, that sequence is translated to TO.
 FROM and TO are a character or a vector of characters.
 If FROM is a character, that character is translated to TO.
 If FROM is a vector of characters, that sequence is translated to TO.

-The first extra-slot of the value is a translation table for reverse mapping."
+The first extra-slot of the value is a translation table for reverse mapping.
+
+FROM and TO may be nil.  If TO is nil, the translation from FROM
+to nothing is defined in the translation table and that element
+is ignored in the reverse map.  If FROM is nil, the translation
+from TO to nothing is defined in the reverse map only.  A vector
+of length zero has the same meaning as specifying nil."

   (let ((tables (vector (make-char-table 'translation-table)
                        (make-char-table 'translation-table)))
        table max-lookup from to idx val)
   (let ((tables (vector (make-char-table 'translation-table)
                        (make-char-table 'translation-table)))
        table max-lookup from to idx val)


@@ -2227,20 +2336,23 @@ The first extra-slot of the value is a translation table for reverse mapping."
          (setq from (cdr elt) to (car elt)))
        (if (characterp from)
            (setq idx from)
          (setq from (cdr elt) to (car elt)))
        (if (characterp from)
            (setq idx from)

-         (setq idx (aref from 0)
-               max-lookup (max max-lookup (length from))))
-       (setq val (aref table idx))
-       (if val
-           (progn
-             (or (consp val)
-                 (setq val (list (cons (vector idx) val))))
-             (if (characterp from)
-                 (setq from (vector from)))
-             (setq val (nconc val (list (cons from to)))))
-         (if (characterp from)
-             (setq val to)
-           (setq val (list (cons from to)))))
-       (aset table idx val))
+         (if (= (length from) 0)
+             (setq idx nil)
+           (setq idx (aref from 0)
+                 max-lookup (max max-lookup (length from)))))
+       (when idx
+         (setq val (aref table idx))
+         (if val
+             (progn
+               (or (consp val)
+                   (setq val (list (cons (vector idx) val))))
+               (if (characterp from)
+                   (setq from (vector from)))
+               (setq val (nconc val (list (cons from to)))))
+           (if (characterp from)
+               (setq val to)
+             (setq val (list (cons from to)))))
+         (aset table idx val)))

       (set-char-table-extra-slot table 1 max-lookup))
     (set-char-table-extra-slot (aref tables 0) 0 (aref tables 1))
     (aref tables 0)))
       (set-char-table-extra-slot table 1 max-lookup))
     (set-char-table-extra-slot (aref tables 0) 0 (aref tables 1))
     (aref tables 0)))