lispref/anti.texi

   1 @c -*-texinfo-*-
   2 @c This is part of the GNU Emacs Lisp Reference Manual.
   3 @c Copyright (C) 1993 Free Software Foundation, Inc.
   4 @c See the file elisp.texi for copying conditions.
   5 @node Antinews, Index, Standard Hooks, Top
   6 @appendix Emacs 18 Antinews
   7
   8 For those users who live backwards in time, here is information about
   9 downgrading to Emacs version 18.  We hope you will enjoy the greater
  10 simplicity that results from the absence of many Emacs 19 features.
  11
  12 @section Old Features in the Lisp Language
  13
  14 The following functions are missing or different in Emacs version 18.
  15
  16 @itemize @bullet
  17 @item
  18 The functions @code{delete}, @code{member}, @code{indirect-function},
  19 @code{map-y-or-n-p}, and @code{invocation-name} have been removed.
  20
  21 @item
  22 The function @code{read} now skips a terminator character that
  23 terminates a symbol when reading from a buffer.  Thus, if you use
  24 @code{read} on a buffer containing @samp{foo(bar)} following point, it
  25 returns @code{foo} and leaves point after the open-parenthesis.  This
  26 means there's no way you can properly read the list @samp{(bar)}, but
  27 that's the way the cookie crumbles.
  28
  29 Because of this simplification, it's no longer necessary for an input
  30 stream function to accept an optional argument.  In Emacs 18, an input
  31 stream is always called with no arguments, and should always return
  32 the next character of input.
  33
  34 @item
  35 The function @code{documentation} takes just one argument;
  36 @code{documentation-property} takes just two.
  37
  38 @item
  39 @code{random} no longer has the optional argument @var{n}.
  40
  41 @item
  42 You can no longer arrange to run a hook if a particular Lisp library is
  43 loaded.  The variable @code{after-load-alist} and the function
  44 @code{eval-after-load} have been removed.
  45
  46 @item
  47 The function @code{autoload} no longer supports autoloading a keymap.
  48
  49 @item
  50 ``Magic'' comments of the form @samp{;;;###autoload} are now just
  51 comments.  They don't do anything in particular except look pretty.
  52 If you want a function to be autoloaded by default, edit @file{loaddefs.h}
  53 by hand.  What do you think editors are for?
  54
  55 @item
  56 We took out the @samp{%S} from the @code{format} function, and the
  57 optional argument @var{noescap} from @code{prin1-to-string}.  We removed
  58 the @code{print-level} variable.
  59 @end itemize
  60
  61 @section Compilation Features
  62
  63 @itemize @bullet
  64 @item
  65 Inline functions are nonexistent in Emacs 18.  We find they make the
  66 calling function unnecessarily large.  (Small size is one of the
  67 features of Emacs 18.)
  68
  69 @item
  70 We eliminated the two special forms, @code{eval-when-compile} and
  71 @code{eval-and-compile}, as well as the @code{compile-defun} command.
  72
  73 @item
  74 When you load a Lisp file or library, you will no longer receive a
  75 warning if the directory contains both a @samp{.elc} file and a new
  76 @samp{.el} file that is newer.  So be on your toes.
  77
  78 @item
  79 We removed the special data type for byte-code functions.  Compiled
  80 functions now work by means of an interpreted function which calls
  81 the function @code{bytecode}.  That function runs the byte code
  82 interpreter.
  83 @end itemize
  84
  85 @section Floating Point Numbers
  86
  87 Emacs 18 doesn't have or need floating point arithmetic built in.
  88 It has a handy Lisp program that allows you to emulate floating point.
  89 You'll have to write programs specially to use it, though.
  90
  91 As a result, certain macros, functions, and predicates no longer handle
  92 specifications for floating point numbers.
  93
  94 The function @code{string-to-number}, the predicate @code{floatp}, and
  95 the variable @code{float-output-format} have all been eliminated.
  96
  97 The functions @code{float}, @code{truncate}, @code{floor}, @code{ceil},
  98 @code{round}, and @code{logb} do not exist; neither do the functions
  99 @code{abs}, @code{cos}, @code{sin}, @code{tan}, @code{acos},
 100 @code{asin}, @code{atan}, @code{exp}, @code{expt}, @code{log10},
 101 @code{log}, or @code{sqrt}.
 102
 103 The @code{format} function no longer handles the specifications
 104 @samp{%e}, @samp{%f} and @samp{%g} for printing floating point numbers;
 105 likewise for @code{message}.
 106
 107 @section Changes in Basic Editing Functions
 108
 109 @itemize @bullet
 110 @item
 111 @code{kill-new} and @code{kill-append}, the primitives for putting text
 112 in the kill ring, have been eliminated.
 113 @c @code{kill-append} seems to exist as a non-documented (no doc string)
 114 @c primitive in emacs 18.  but news.texi said it was new for 19.
 115
 116 @item
 117 The variables @code{interprogram-paste-function} and
 118 @code{interprogram-cut-function} have been removed in Emacs 18.
 119
 120 In addition, there's no need for @code{mark-active} and
 121 @code{deactivate-mark} because there is no Transient Mark mode.  We also
 122 removed the hooks @code{activate-mark-hook} and
 123 @code{deactivate-mark-hook}.
 124
 125 @item
 126 The @code{kill-region} function can no longer be used in read-only
 127 buffers.  The @code{compare-buffer-substrings} and @code{current-kill}
 128 functions have been removed.
 129
 130 @item
 131 The variable @code{overwrite-mode-binary} has been removed.
 132
 133 @item
 134 The function @code{move-to-column} allows just one argument,
 135 @var{column}.
 136
 137 @item
 138 The search functions now just return @code{t} when successful.  This
 139 affects the functions @code{search-forward}, @code{search-backward},
 140 @code{word-search-forward}, @code{word-search-backward},
 141 @code{re-search-forward}, and @code{re-search-backward}.
 142
 143 @item
 144 When you do regular expression searching or matching, there is a fixed
 145 limit of ten @samp{\(@dots{}\)} pairs that you can get information about
 146 with @code{match-beginning} and @code{match-end}.  Moreover,
 147 @code{save-match-data} does not exist; you must use an explicit
 148 @code{unwind-protect} to save the match data.
 149
 150 @item
 151 @code{translate-region} is gone.
 152
 153 @item
 154 The variables @code{before-change-function},
 155 @code{after-change-function}, and @code{first-change-hook} have been
 156 eliminated.
 157
 158 @item
 159 The second argument to @code{insert-abbrev-table-description} is no
 160 longer optional.
 161 @end itemize
 162
 163 @section Text Properties
 164
 165 We eliminated text properties.
 166
 167 @section Features for Files
 168
 169 Many file-related functions have been eliminated or simplified.  Here is
 170 a basic listing of these functions.
 171
 172 The functions @code{file-accessible-directory-p}, @code{file-truename},
 173 @code{make-directory}, @code{delete-directory},
 174 @code{set-visited-file-modtime}, @code{directory-abbrev-alist},
 175 @code{abbreviate-file-name}, @code{write-region},
 176 @code{write-contents-hooks}, @code{after-save-hook},
 177 @code{set-default-file-modes}, @code{default-file-modes}, and
 178 @code{unix-sync} have been eliminated.
 179
 180 We got rid of the ``initial file name'' argument to
 181 @code{read-file-name}.
 182
 183 Additionally, we removed the 12th element from the list returned by
 184 @code{file-attributes}.
 185
 186 @code{directory-files} always sorts the list of files.  It's not user
 187 friendly to process the files in any haphazard order.
 188
 189 We eliminated the variables @code{write-contents-hooks} and
 190 @code{local-write-file-hooks}.
 191
 192 @section Making Certain File Names ``Magic''
 193
 194 There are no more magic filenames.  Sorry, but all the mana has been
 195 used up.
 196
 197 @section Frames
 198
 199 There is only one frame in Emacs 18, so all of the frame functions have
 200 been eliminated.
 201
 202 @section X Window System Features
 203
 204 We have simplified the way Emacs and X interact by removing a great deal
 205 of creeping featurism.
 206
 207 @itemize @bullet
 208 @item
 209 The functions @code{mouse-position} and @code{set-mouse-position}, and
 210 the special form @code{track-mouse} have been eliminated.
 211
 212 @item
 213 Likewise, the functions @code{x-set-selection}, @code{x-set-cut-buffer},
 214 @code{x-close-current-connection}, and @code{x-open-connection} have all
 215 been removed from Emacs Lisp 18.
 216
 217 @item
 218 We removed a series of functions that gave information about the X
 219 server and the screen you were using; after all, the whole point of X is
 220 that all servers are equivalent.  The names of the removed functions
 221 are: @code{x-display-screens}, @code{x-server-version},
 222 @code{x-server-vendor}, @code{x-display-pixel-height},
 223 @code{x-display-mm-height}, @code{x-display-pixel-width},
 224 @code{x-display-mm-width}, @code{x-display-backing-store},
 225 @code{x-display-save-under}, @code{x-display-planes},
 226 @code{x-display-visual-class}, @code{x-display-color-p}, and
 227 @code{x-display-color-cells}.
 228
 229 Additionally, we removed the variable @code{x-no-window-manager} and the
 230 functions @code{x-synchronize} and @code{x-get-resource}.
 231
 232 We didn't abolish @code{x-display-color-p}, but we renamed it to
 233 @code{x-color-display-p}.  We did abolish @code{x-color-defined-p}.
 234
 235 @item
 236 @code{x-popup-menu} no longer accepts a keymap for its first argument.
 237
 238 @item
 239 We removed both the function @code{x-rebind-key} and the related
 240 function @code{x-rebind-keys}.
 241
 242 @item
 243 We abolished @code{x-parse-geometry}.
 244 @end itemize
 245
 246 @section Window Actions that Were No Longer Useful
 247
 248 Various behaviors of windows in Emacs 19 were obsolete by the time Emacs
 249 18 was due to come out.  We have removed them.  These changes are listed
 250 below.
 251
 252 @itemize @bullet
 253 @item
 254 We removed the functions @code{window-at}, @code{window-minibuffer-p},
 255 @code{set-window-dedicated-p}, @code{coordinates-in-window-p},
 256 @code{walk-windows}, @code{window-dedicated-p}, and @code{window-end}.
 257
 258 @item
 259 We removed the variables @code{pop-up-frames},
 260 @code{pop-up-frame-function}, @code{display-buffer-function}, and
 261 @code{other-window-scroll-buffer}.
 262
 263 @item
 264 The function @code{minibuffer-window} no longer accepts a frame as
 265 argument, since frames as objects do not exist in Emacs version 18.  It
 266 returns the window used for minibuffers.
 267
 268 @item
 269 The functions @code{next-window} and @code{previous-window} no longer
 270 accept the @var{all-frames} argument since there is just one frame.
 271
 272 @item
 273 The functions @code{get-lru-window}, @code{get-largest-window},
 274 @code{get-buffer-window}, and @code{get-buffer-window} also no longer
 275 take the optional argument @var{all-frames} because there is just one
 276 frame to search.
 277 @end itemize
 278
 279 @section Display Features
 280
 281 @itemize @bullet
 282 @item
 283 There are no overlays, and no faces.
 284
 285 @item
 286 We eliminated the mode line spec @samp{%l} that in later versions used
 287 to display the current line number.  We removed the variables
 288 @code{line-number-mode} and @code{line-number-display-limit}.
 289
 290 @item
 291 @code{baud-rate} is now a function rather than a variable.
 292
 293 @item
 294 You can no longer call @code{message} with @code{nil} as the only
 295 argument; therefore, you can not reliably make the contents of the
 296 minibuffer visible.
 297
 298 @item
 299 The variable @code{temp-buffer-show-function} has been renamed
 300 @code{temp-buffer-show-hook}.
 301
 302 @item
 303 We removed the function @code{force-mode-line-update}.  Use
 304 the following idiom instead:
 305
 306 @example
 307 (set-buffer-modified-p (buffer-modified-p))
 308 @end example
 309
 310 @item
 311 Display tables no longer exist.  We know what the @sc{ASCII} characters
 312 should look like, and we made them look that way.
 313 @end itemize
 314
 315 @section Working with Input Events
 316
 317 The big news about input events is that we got rid of function key
 318 and mouse events.  Now the only input events are characters.
 319 What's more, these characters now have to be in the range of 0 to 127,
 320 optionally with a meta bit.  This makes for big simplifications.
 321
 322 @itemize @bullet
 323 @item
 324 Functions like @code{define-key}, @code{global-set-key},
 325 @code{read-key-sequence}, and @code{local-set-key} used to accept
 326 strings or vectors in Emacs 19; now they only accept strings.
 327
 328 @item
 329 The documentation functions (@code{single-key-description},
 330 @code{key-description}, etc.) also no longer accept vectors, but they do
 331 accept strings.
 332
 333 @item
 334 We removed the @code{read-event}, @code{event-start},
 335 @code{posn-window}, @code{posn-point}, @code{posn-col-row},
 336 @code{posn-timestamp}, @code{scroll-bar-scale}, and @code{event-end}
 337 functions, since they were only useful for non-character events.
 338
 339 @item
 340 We removed the @code{unread-command-events} and @code{last-event-frame}
 341 variables.
 342
 343 @item
 344 The functions @code{this-command-keys} and @code{recent-keys} now always
 345 return a string.  Likewise, a keyboard macro's definition can only be a
 346 string, not a vector.
 347
 348 @item
 349 We eliminated @samp{e} as an interactive specification since it
 350 was useful only with non-character events.
 351
 352 @item
 353 In Emacs 18, we represent Meta characters as character objects with the
 354 same encoding used in strings: 128 plus the corresponding non-Meta
 355 @sc{ASCII} character.
 356 @end itemize
 357
 358 @section Menus
 359
 360 You can no longer define menus as keymaps; good system design requires
 361 crafting a special-purpose interface for each facility, so it can
 362 precisely fit the requirements of that facility.  We decided that
 363 unifying keymaps and menus was simply too much of a strain.
 364
 365 In Emacs 18, you can only activate menus with the mouse.  Using them
 366 with a keyboard was too confusing for too many users.
 367
 368 Emacs 18 has no menu bars.  All functions and variables related to the
 369 menu bar have been eliminated.
 370
 371 @section Changes in Minibuffer Features
 372
 373 The minibuffer history feature has been eliminated.  Thus, we removed
 374 the optional argument @var{hist} from the minibuffer input functions
 375 @code{read-from-minibuffer} and @code{completing-read}.
 376
 377 The @var{initial} argument to @code{read-from-minibuffer} and other
 378 minibuffer input functions can no longer be a cons cell
 379 @code{(@var{string} . @var{position})}.
 380
 381 In the function @code{read-no-blanks-input}, the @var{initial} argument
 382 is no longer optional.
 383
 384 @section New Features for Defining Commands
 385
 386 @itemize @bullet
 387 @item
 388 The special meaning of @samp{@@} in an interactive specification has
 389 been eliminated.
 390
 391 @item
 392 Emacs 18 does not support use of format-style @samp{%}-sequences in the
 393 prompt strings in interactive specifications.
 394
 395 @item
 396 The property @code{enable-recursive-minibuffers} no longer has any
 397 special meaning.
 398 @end itemize
 399
 400 @section Removed Features for Reading Input
 401
 402 We removed the third argument (@var{meta}) from the function
 403 @code{set-input-mode}.  Consequently, we added the variable
 404 @code{meta-flag}; set it to @code{t} to enable use of a Meta key, and
 405 to @code{nil} to disable it.  (Those are the only two alternatives.)
 406
 407 We also removed the variable @code{extra-keyboard-modifiers}.
 408
 409 We removed the function @code{keyboard-translate} and the variables
 410 @code{num-input-keys} and @code{function-key-map}.
 411
 412 @section Removed Syntax Table Features
 413
 414 @itemize @bullet
 415 @item
 416 We eliminated the functions @code{skip-syntax-forward},
 417 @code{skip-syntax-backward}, @code{forward-comment}.
 418
 419 @item
 420 We removed the syntax flag for ``prefix syntax'' and the flag for the
 421 alternate comment style.  Emacs 18 supports only one style of comment
 422 in any given syntax table.
 423
 424 @item
 425 We abolished the variable @code{words-include-escapes}.
 426 @end itemize
 427
 428 @section The Case Table
 429
 430 Case tables do not exist in Emacs 18.  Due to this change, we have
 431 removed the associated functions @code{set-standard-case-table},
 432 @code{standard-case-table}, @code{current-case-table},
 433 @code{set-case-table}, and @code{set-case-syntax-pair}.
 434
 435 @section Features for Dealing with Buffers
 436
 437 @itemize @bullet
 438 @item
 439 We eliminated several functions for dealing with buffers:
 440 @code{buffer-modified-tick} and @code{generate-new-buffer-name}.
 441
 442 @item
 443 We renamed @code{buffer-disable-undo} to @code{buffer-flush-undo}---a
 444 more picturesque name, you will agree.
 445
 446 @item
 447 The function @code{other-buffer} takes just one argument in Emacs 18.
 448
 449 @item
 450 The function @code{rename-buffer} now requires you to specify precisely
 451 the new name you want.
 452
 453 @item
 454 We removed the local variable @code{list-buffers-directory}.
 455
 456 @item
 457 We got rid of the hook @code{kill-buffer-hook}.
 458 @end itemize
 459
 460 @section Local Variables Features
 461
 462 @itemize @bullet
 463 @item
 464 The function @code{kill-all-local-variables} always eliminates all
 465 buffer-local variables of the current buffer.  No more exceptions.
 466
 467 @item
 468 Making a variable buffer-local when it is void now sets it to
 469 @code{nil}.
 470
 471 @item
 472 We eliminated the functions @code{default-boundp}, because it is no
 473 longer possible for the default binding of a variable to be void.
 474
 475 @item
 476 The special forms @code{defconst} and @code{defvar} now set the
 477 variable's local value rather than its default value when the variable
 478 is local in the current buffer.
 479 @end itemize
 480
 481 @section Features for Subprocesses
 482
 483 @code{call-process} and @code{call-process-region} no longer indicate
 484 the termination status of the subprocess.  We call on users to have faith
 485 that the subprocess executed properly.
 486
 487 @itemize
 488 @item
 489 The standard asynchronous subprocess features do not work on VMS;
 490 instead, special VMS asynchronous subprocess functions have been added.
 491 Since they are only for VMS, we can't be bothered documenting them;
 492 sorry.  Use the source, Luke!
 493
 494 @item
 495 The function @code{signal-process} has been removed.
 496
 497 @item
 498 We eliminated the transaction queue feature, and the associated
 499 functions @code{tq-create}, @code{tq-enqueue}, and @code{tq-close}.
 500 @end itemize
 501
 502 @section Dealing with Times And Time Delays
 503
 504 @itemize @bullet
 505 @item
 506 We removed the functions @code{current-time}, @code{current-time-zone},
 507 @code{run-at-time}, and @code{cancel-timer}.
 508
 509 @item
 510 The function @code{current-time-string} no longer accepts any optional
 511 arguments.
 512
 513 @item
 514 The functions @code{sit-for} and @code{sleep-for} no longer allow an
 515 optional argument to let you specify the time period in milliseconds;
 516 just in seconds.  Additionally, we took out the optional third argument
 517 @var{nodisp} from @code{sit-for}.
 518
 519 @item
 520 We removed the optional second and third arguments from the
 521 @code{accept-process-output} function.  It accepts just one argument,
 522 the process.
 523 @end itemize
 524
 525 @need 3000
 526
 527 @section Features not Available for Lisp Debuggers
 528
 529 @itemize @bullet
 530 @item
 531 In Emacs 18, you can no longer specify to invoke the Lisp debugger only
 532 upon encountering certain types of errors.  Any non-@code{nil} value for
 533 the variable @code{debug-on-error} says to invoke the debugger for any
 534 error whatever.
 535
 536 @item
 537 We removed the variable @code{command-debug-status} and the function
 538 @code{backtrace-frame}.
 539 @end itemize
 540
 541 @section Memory Allocation Changes
 542
 543 We removed the function @code{memory-limit}.
 544
 545 The list returned by @code{garbage-collect} no longer contains an
 546 element to describe floating point numbers, since there aren't any
 547 floating point numbers in Emacs 18.
 548
 549 @section Hook Changes
 550
 551 @itemize @bullet
 552 @item
 553 We removed the hooks @code{pre-abbrev-expand-hook},
 554 @code{pre-command-hook}, @code{post-command-hook}, and
 555 @code{auto-save-hook}.
 556
 557 @item
 558 We removed the variable
 559 @code{revert-buffer-insert-file-contents-function}.
 560
 561 @item
 562 We also removed the new function @code{add-hook}; you will have to set
 563 your hooks by hand.  If you want to get really into the swing of things,
 564 set your hook variables the archaic way: store just one function rather
 565 than a list of functions.  But that is optional.
 566
 567 @item
 568 The variable @code{lisp-indent-hook} has been renamed to
 569 @code{lisp-indent-function}.
 570
 571 @item
 572 The variable @code{auto-fill-function} has been renamed to
 573 @code{auto-fill-hook}.
 574
 575 @item
 576 The @code{blink-paren-function} has been renamed to
 577 @code{blink-paren-hook}.
 578
 579 @item
 580 The variable @code{temp-buffer-show-function} has been renamed to
 581 @code{temp-buffer-show-hook}.
 582 @end itemize