etc/NEWS.unicode

   1 GNU Emacs NEWS -- history of user-visible changes.
   2
   3 Copyright (C) 2007 Free Software Foundation, Inc.
   4 Copyright (C) 2007
   5   National Institute of Advanced Industrial Science and Technology (AIST)
   6   Registration Number H14PRO021
   7 See the end of the file for license conditions.
   8
   9 Please send Emacs bug reports to bug-gnu-emacs@gnu.org.
  10 If possible, use M-x report-emacs-bug.
  11
  12 This file is about changes in the Emacs "unicode" branch.
  13
  14 \f
  15 * Changes in Emacs Unicode
  16
  17 ** The Emacs character set is now a superset of Unicode.
  18 (It has about four times the code space, which should be plenty).
  19
  20 The internal encoding used for buffers and strings is now
  21 Unicode-based and called `utf-8-emacs'.  utf-8-emacs is backwards
  22 compatible with the UTF-8 encoding of Unicode.  The `emacs-mule'
  23 coding system can still read and write data in the old internal
  24 encoding.
  25
  26 Since the internal encoding is also used by default for byte-compiled
  27 files -- i.e. the normal coding system for byte-compiled Lisp files is
  28 now utf-8-Emacs -- Lisp containing non-ASCII characters which is
  29 compiled by Emacs 23 can't be read by earlier versions of Emacs.  Files
  30 compiled by Emacs 20, 21, or 22 are loaded correctly as emacs-mule
  31 (whether or not they contain multibyte characters), which makes loading
  32 them somewhat slower than Emacs 23-compiled files.  Thus it may be worth
  33 recompiling existing .elc files which don't need to be shared with older
  34 Emacsen.
  35
  36 ** There are assorted new coding systems/aliases -- see
  37 M-x list-coding-systems.
  38
  39 ** New charset implementation with many new charsets.
  40 See M-x list-character-sets.  New charsets can be defined conveniently
  41 as tables of unicodes.
  42
  43 The dimension of a charset is now 0, 1, 2, or 3, and the size of each
  44 dimension is no longer limited to 94 or 96.
  45
  46 A dynamic charset priority list is used to infer the charset of
  47 characters for display.
  48
  49 ** New minor mode Auto Composition Mode composes characters automatically
  50 when they are displayed.  This mode is globally on by default.
  51
  52 ** Emacs now supports local fonts (fonts installed in the same machine
  53 as Emacs is running) by freetype and fontconfig libraries.  On X, they
  54 are drived via Xft library with antialias support.  Fontconfig-like
  55 font names (e.g. monospace-12) are also accepted.
  56
  57 ** New language environments Chinese-GBK, Chinese-GB18030, and
  58 TaiViet.
  59
  60 ** The following facilities are obsolete:
  61
  62 Minor modes: unify-8859-on-encoding-mode, unify-8859-on-decoding-mode
  63
  64 \f
  65 * Lisp changes in Emacs Unicode
  66
  67 ** Character code, representation, and charset changes.
  68
  69 Now character code space is 0x0..0x3FFFFF with no gap.  Among them,
  70 characters of code 0x0..0x10FFFF are Unicode characters of the same
  71 code points.  Characters of code 0x3FFF80..0x3FFFFF are raw 8-bit
  72 bytes.
  73
  74 Generic characters no longer exist.
  75
  76 In buffer and string, characters are represented by UTF-8 byte
  77 sequence in a multibyte buffer/string.
  78
  79 The concept of charset is changed.  A single character may belong to
  80 multiple charset (e.g. a-grave (U+00E0) belongs to charsets unicode,
  81 iso-8859-1, iso-8859-3, and etc).
  82
  83 *** The new function `characterp' returns t if and only if the argument
  84 is a character.
  85
  86 *** The new function `max-char' returns the maximum character code
  87 (currently it is #x3FFFFF).
  88
  89 *** The function `encode-char' and `decode-char' now accepts any
  90 character sets.
  91
  92 *** The function `define-charset' now accepts completely different
  93 form of argments (old-style arguments still works).
  94
  95 *** The new function `define-charset-alias' defines an alias of a
  96 charset.
  97
  98 *** The value of the function `char-charset' depends of the current
  99 priorities of charsets.
 100
 101 *** The new function `charset-priority-list' returns the list of
 102 charsets ordered by priority.
 103
 104 *** The new function `set-charset-priority' sets pliorities of
 105 charsets.
 106
 107 *** The new function `unibyte-charset' returns the current unibyte
 108 charset.  The unibyte charset determins how unibyte/multibyte
 109 conversion is done.
 110
 111 *** The new function `set-unibyte-charset' sets the unibyte charset.
 112
 113 *** The new function `unibyte-string' make a unibyte string from
 114 bytes.
 115
 116 ** Code conversion changes
 117
 118 *** The new function `define-coding-system' should be used to define a
 119 coding system instead of `make-coding-system' (which is obsolete now).
 120
 121 *** The functions `encode-coding-region' and `decode-coding-region'
 122 have the optional 4th argument to specify where the result of
 123 conversion should go.
 124
 125 *** The functions `encode-coding-string' and `decode-coding-string'
 126 have the optional 4th argument specifying a buffer to store the result
 127 of conversion.
 128
 129 *** The new fuction `with-coding-priority' executs the body part with
 130 the specified coding system priority order.
 131
 132 *** The new function `check-coding-systems-region' checks if the text
 133 in the region is encodable by the specified coding systems.
 134
 135 *** The new function `coding-system-aliases' returns a list of aliases
 136 of a coding system.
 137
 138 *** The new function `coding-system-charset-list' returns a list of
 139 charsets supported by a coding system.
 140
 141 *** The new funciton `coding-system-priority-list' returns a list of
 142 coding systems ordered by their priorities.
 143
 144 *** Thew new function `set-coding-system-priority' sets priorities of
 145 coding systems.
 146
 147 ** Composition changes
 148
 149 *** New functions and variables `auto-composition-mode' and
 150 `global-auto-composition-mode' toggles the new minor mode Auto
 151 Composition Mode locally and globally.
 152
 153 *** New variable `auto-composition-function' is a function used in
 154 Auto Composition Mode to compose characters.  The default value is the
 155 function `auto-compose-chars'.
 156
 157 *** New variable `auto-compose-current-font' is set to the current
 158 font-object while characters are being composed in Auto Composition
 159 Mode.
 160
 161 ** Font Backend changes.
 162
 163 *** New frame parameter `font-backend' specifies a list of
 164 font-backends supported by the frame's graphic device.  On X, they are
 165 currently `x' and `xft'.
 166
 167 *** New function `fontp' checks if the argument is a font-spec
 168 or font-entity.
 169
 170 *** New function `font-spec' creates a new font-spec object.
 171
 172 *** New function `font-get' returns a font property value.
 173
 174 *** New function `font-put' sets a font property value.
 175
 176 *** New function `list-fonts' returns a list of font-entities matching
 177 with the give specificaiton.
 178
 179 *** New function `list-families' returns a list family names of
 180 available fonts.
 181
 182 *** New function `font-font' returns a font-entity best matching with
 183 the given specification.
 184
 185 *** New function `font-xlfd-name' returns an XLFD name of a give font
 186 (font-spec, font-entity, or font-object).
 187
 188 *** New function `clear-font-cache' clears all font caches.
 189
 190 ** The function get-char-code-property now accepts many Unicode base
 191 character properties.  They are `name', `general-category',
 192 `canonical-combining-class', `bidi-class', `decomposition',
 193 `decimal-digit-value', `digit-value', `numeric-value', `mirrord',
 194 `old-name', `iso-10646-comment', `uppercase', `lowercase', and
 195 `titlecase'.
 196
 197 ** Thew new function `define-char-code-property' defines a character
 198 code property.
 199
 200 ** The new function `char-code-property-description' returns the
 201 description string of a cahracter code property.
 202
 203 *** The new variable `find-word-boundary-function-table' is a
 204 char-table of functions to search for a word boundary.
 205
 206 *** The new variable `char-script-table' is a char-table of script
 207 names.
 208
 209 *** The new variable `char-width-table' is a char-table of character
 210 widths.
 211
 212 *** The new variable `print-charset-text-property' controls how to
 213 handle `charset' text property on printing a string.
 214
 215 *** Thew new variable `printable-chars' is a char-table defining if a
 216 character is printable or not.
 217
 218 *** The new function `robin-define-package' defines a Robin package
 219 which is an input method system different from Quail.
 220
 221 *** The new function `robin-modify-package' modifies an existing Robin
 222 package.
 223
 224 *** The new function `robin-use-package' start using a Robin package
 225 as an input method.
 226
 227 ** The functions `modify-syntax-entry' and `modify-category-entry' now
 228 accepts a cons of characters as the first argument, and modify all
 229 entries in that range of characters.
 230
 231 ** The function `set-fontset-font' now accepts a script name as the
 232 second argument, and has the optional 5th argument to control how to
 233 set the font.
 234
 235 ** The functions `char-bytes', `chars-in-region', `set-coding-priority',
 236 , `make-coding-system', and `char-valid-p' are now obsolete.
 237
 238 \f
 239 * Incompatible Lisp changes
 240
 241 ** The behavior of map-char-table has changed.  It may call the
 242 specified function with a cons (FROM . TO) as a key if characters in
 243 that range has the same value.
 244
 245 ** The value of the function `charset-id' is now always 0.
 246
 247 ** The functions `register-char-codings' and `coding-system-spec' are
 248 deleted.
 249
 250 \f
 251 ----------------------------------------------------------------------
 252 This file is part of GNU Emacs.
 253
 254 GNU Emacs is free software; you can redistribute it and/or modify
 255 it under the terms of the GNU General Public License as published by
 256 the Free Software Foundation; either version 2, or (at your option)
 257 any later version.
 258
 259 GNU Emacs is distributed in the hope that it will be useful,
 260 but WITHOUT ANY WARRANTY; without even the implied warranty of
 261 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 262 GNU General Public License for more details.
 263
 264 You should have received a copy of the GNU General Public License
 265 along with GNU Emacs; see the file COPYING.  If not, write to the
 266 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 267 Boston, MA 02110-1301, USA.
 268
 269 \f
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 273 end:
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