Emacs 18 Antinews

For those users who live backwards in time, here is information about downgrading to Emacs version 18. We hope you will enjoy the greater simplicity that results from the absence of many Emacs 19 features.

Old Features in the Lisp Language

The following functions are missing or different in Emacs version 18.

• The functions delete, member, indirect-function, map-y-or-n-p, and invocation-name have been removed.
• The function read now skips a terminator character that terminates a symbol when reading from a buffer. Thus, if you use read on a buffer containing `foo(bar)' following point, it returns foo and leaves point after the open-parenthesis. This means there's no way you can properly read the list `(bar)', but that's the way the cookie crumbles. Because of this simplification, it's no longer necessary for an input stream function to accept an optional argument. In Emacs 18, an input stream is always called with no arguments, and should always return the next character of input.
• The function documentation takes just one argument; documentation-property takes just two.
• random no longer has the optional argument n.
• You can no longer arrange to run a hook if a particular Lisp library is loaded. The variable after-load-alist and the function eval-after-load have been removed.
• The function autoload no longer supports autoloading a keymap.
• "Magic" comments of the form `;;;###autoload' are now just comments. They don't do anything in particular except look pretty. If you want a function to be autoloaded by default, edit `loaddefs.h' by hand. What do you think editors are for?
• We took out the `%S' from the format function, and the optional argument noescap from prin1-to-string. We removed the print-level variable.

Compilation Features

• Inline functions are nonexistent in Emacs 18. We find they make the calling function unnecessarily large. (Small size is one of the features of Emacs 18.)
• We eliminated the two special forms, eval-when-compile and eval-and-compile, as well as the compile-defun command.
• When you load a Lisp file or library, you will no longer receive a warning if the directory contains both a `.elc' file and a new `.el' file that is newer. So be on your toes.
• We removed the special data type for byte-code functions. Compiled functions now work by means of an interpreted function which calls the function bytecode. That function runs the byte code interpreter.

Floating Point Numbers

Emacs 18 doesn't have or need floating point arithmetic built in. It has a handy Lisp program that allows you to emulate floating point. You'll have to write programs specially to use it, though.

As a result, certain macros, functions, and predicates no longer handle specifications for floating point numbers.

The function string-to-number, the predicate floatp, and the variable float-output-format have all been eliminated.

The functions float, truncate, floor, ceil, round, and logb do not exist; neither do the functions abs, cos, sin, tan, acos, asin, atan, exp, expt, log10, log, or sqrt.

The format function no longer handles the specifications `%e', `%f' and `%g' for printing floating point numbers; likewise for message.

Changes in Basic Editing Functions

• kill-new and kill-append, the primitives for putting text in the kill ring, have been eliminated.
• The variables interprogram-paste-function and interprogram-cut-function have been removed in Emacs 18. In addition, there's no need for mark-active and deactivate-mark because there is no Transient Mark mode. We also removed the hooks activate-mark-hook and deactivate-mark-hook.
• The kill-region function can no longer be used in read-only buffers. The compare-buffer-substrings and current-kill functions have been removed.
• The variable overwrite-mode-binary has been removed.
• The function move-to-column allows just one argument, column.
• The search functions now just return t when successful. This affects the functions search-forward, search-backward, word-search-forward, word-search-backward, re-search-forward, and re-search-backward.
• When you do regular expression searching or matching, there is a fixed limit of ten `\(...\)' pairs that you can get information about with match-beginning and match-end. Moreover, save-match-data does not exist; you must use an explicit unwind-protect to save the match data.
• translate-region is gone.
• The variables before-change-function, after-change-function, and first-change-hook have been eliminated.
• The second argument to insert-abbrev-table-description is no longer optional.

Text Properties

We eliminated text properties.

Features for Files

Many file-related functions have been eliminated or simplified. Here is a basic listing of these functions.

The functions file-accessible-directory-p, file-truename, make-directory, delete-directory, set-visited-file-modtime, directory-abbrev-alist, abbreviate-file-name, write-region, write-contents-hooks, after-save-hook, set-default-file-modes, default-file-modes, and unix-sync have been eliminated.

We got rid of the "initial file name" argument to read-file-name.

Additionally, we removed the 12th element from the list returned by file-attributes.

directory-files always sorts the list of files. It's not user friendly to process the files in any haphazard order.

We eliminated the variables write-contents-hooks and local-write-file-hooks.

Making Certain File Names "Magic"

There are no more magic filenames. Sorry, but all the mana has been used up.

Frames

There is only one frame in Emacs 18, so all of the frame functions have been eliminated.

X Window System Features

We have simplified the way Emacs and X interact by removing a great deal of creeping featurism.

• The functions mouse-position and set-mouse-position, and the special form track-mouse have been eliminated.
• Likewise, the functions x-set-selection, x-set-cut-buffer, x-close-current-connection, and x-open-connection have all been removed from Emacs Lisp 18.
• We removed a series of functions that gave information about the X server and the screen you were using; after all, the whole point of X is that all servers are equivalent. The names of the removed functions are: x-display-screens, x-server-version, x-server-vendor, x-display-pixel-height, x-display-mm-height, x-display-pixel-width, x-display-mm-width, x-display-backing-store, x-display-save-under, x-display-planes, x-display-visual-class, x-display-color-p, and x-display-color-cells. Additionally, we removed the variable x-no-window-manager and the functions x-synchronize and x-get-resource. We didn't abolish x-display-color-p, but we renamed it to x-color-display-p. We did abolish x-color-defined-p.
• x-popup-menu no longer accepts a keymap for its first argument.
• We removed both the function x-rebind-key and the related function x-rebind-keys.
• We abolished x-parse-geometry.

Window Actions that Were No Longer Useful

Various behaviors of windows in Emacs 19 were obsolete by the time Emacs 18 was due to come out. We have removed them. These changes are listed below.

• We removed the functions window-at, window-minibuffer-p, set-window-dedicated-p, coordinates-in-window-p, walk-windows, window-dedicated-p, and window-end.
• We removed the variables pop-up-frames, pop-up-frame-function, display-buffer-function, and other-window-scroll-buffer.
• The function minibuffer-window no longer accepts a frame as argument, since frames as objects do not exist in Emacs version 18. It returns the window used for minibuffers.
• The functions next-window and previous-window no longer accept the all-frames argument since there is just one frame.
• The functions get-lru-window, get-largest-window, get-buffer-window, and get-buffer-window also no longer take the optional argument all-frames because there is just one frame to search.

Display Features

• There are no overlays, and no faces.
• We eliminated the mode line spec `%l' that in later versions used to display the current line number. We removed the variables line-number-mode and line-number-display-limit.
• baud-rate is now a function rather than a variable.
• You can no longer call message with nil as the only argument; therefore, you can not reliably make the contents of the minibuffer visible.
• The variable temp-buffer-show-function has been renamed temp-buffer-show-hook.
• We removed the function force-mode-line-update. Use the following idiom instead:

  (set-buffer-modified-p (buffer-modified-p))
  

• Display tables no longer exist. We know what the ASCII characters should look like, and we made them look that way.

Working with Input Events

The big news about input events is that we got rid of function key and mouse events. Now the only input events are characters. What's more, these characters now have to be in the range of 0 to 127, optionally with a meta bit. This makes for big simplifications.

• Functions like define-key, global-set-key, read-key-sequence, and local-set-key used to accept strings or vectors in Emacs 19; now they only accept strings.
• The documentation functions (single-key-description, key-description, etc.) also no longer accept vectors, but they do accept strings.
• We removed the read-event, event-start, posn-window, posn-point, posn-col-row, posn-timestamp, scroll-bar-scale, and event-end functions, since they were only useful for non-character events.
• We removed the unread-command-events and last-event-frame variables.
• The functions this-command-keys and recent-keys now always return a string. Likewise, a keyboard macro's definition can only be a string, not a vector.
• We eliminated `e' as an interactive specification since it was useful only with non-character events.
• In Emacs 18, we represent Meta characters as character objects with the same encoding used in strings: 128 plus the corresponding non-Meta ASCII character.

Menus

You can no longer define menus as keymaps; good system design requires crafting a special-purpose interface for each facility, so it can precisely fit the requirements of that facility. We decided that unifying keymaps and menus was simply too much of a strain.

In Emacs 18, you can only activate menus with the mouse. Using them with a keyboard was too confusing for too many users.

Emacs 18 has no menu bars. All functions and variables related to the menu bar have been eliminated.

Changes in Minibuffer Features

The minibuffer history feature has been eliminated. Thus, we removed the optional argument hist from the minibuffer input functions read-from-minibuffer and completing-read.

The initial argument to read-from-minibuffer and other minibuffer input functions can no longer be a cons cell (string . position).

In the function read-no-blanks-input, the initial argument is no longer optional.

New Features for Defining Commands

• The special meaning of `@' in an interactive specification has been eliminated.
• Emacs 18 does not support use of format-style `%'-sequences in the prompt strings in interactive specifications.
• The property enable-recursive-minibuffers no longer has any special meaning.

Removed Features for Reading Input

We removed the third argument (meta) from the function set-input-mode. Consequently, we added the variable meta-flag; set it to t to enable use of a Meta key, and to nil to disable it. (Those are the only two alternatives.)

We also removed the variable extra-keyboard-modifiers.

We removed the function keyboard-translate and the variables num-input-keys and function-key-map.

Removed Syntax Table Features

• We eliminated the functions skip-syntax-forward, skip-syntax-backward, forward-comment.
• We removed the syntax flag for "prefix syntax" and the flag for the alternate comment style. Emacs 18 supports only one style of comment in any given syntax table.
• We abolished the variable words-include-escapes.

The Case Table

Case tables do not exist in Emacs 18. Due to this change, we have removed the associated functions set-standard-case-table, standard-case-table, current-case-table, set-case-table, and set-case-syntax-pair.

Features for Dealing with Buffers

• We eliminated several functions for dealing with buffers: buffer-modified-tick and generate-new-buffer-name.
• We renamed buffer-disable-undo to buffer-flush-undo---a more picturesque name, you will agree.
• The function other-buffer takes just one argument in Emacs 18.
• The function rename-buffer now requires you to specify precisely the new name you want.
• We removed the local variable list-buffers-directory.
• We got rid of the hook kill-buffer-hook.

Local Variables Features

• The function kill-all-local-variables always eliminates all buffer-local variables of the current buffer. No more exceptions.
• Making a variable buffer-local when it is void now sets it to nil.
• We eliminated the functions default-boundp, because it is no longer possible for the default binding of a variable to be void.
• The special forms defconst and defvar now set the variable's local value rather than its default value when the variable is local in the current buffer.

Features for Subprocesses

call-process and call-process-region no longer indicate the termination status of the subprocess. We call on users to have faith that the subprocess executed properly.

• The standard asynchronous subprocess features do not work on VMS; instead, special VMS asynchronous subprocess functions have been added. Since they are only for VMS, we can't be bothered documenting them; sorry. Use the source, Luke!
• The function signal-process has been removed.
• We eliminated the transaction queue feature, and the associated functions tq-create, tq-enqueue, and tq-close.

Dealing with Times And Time Delays

• We removed the functions current-time, current-time-zone, run-at-time, and cancel-timer.
• The function current-time-string no longer accepts any optional arguments.
• The functions sit-for and sleep-for no longer allow an optional argument to let you specify the time period in milliseconds; just in seconds. Additionally, we took out the optional third argument nodisp from sit-for.
• We removed the optional second and third arguments from the accept-process-output function. It accepts just one argument, the process.

Features not Available for Lisp Debuggers

• In Emacs 18, you can no longer specify to invoke the Lisp debugger only upon encountering certain types of errors. Any non-nil value for the variable debug-on-error says to invoke the debugger for any error whatever.
• We removed the variable command-debug-status and the function backtrace-frame.

Memory Allocation Changes

We removed the function memory-limit.

The list returned by garbage-collect no longer contains an element to describe floating point numbers, since there aren't any floating point numbers in Emacs 18.

Hook Changes

• We removed the hooks pre-abbrev-expand-hook, pre-command-hook, post-command-hook, and auto-save-hook.
• We removed the variable revert-buffer-insert-file-contents-function.
• We also removed the new function add-hook; you will have to set your hooks by hand. If you want to get really into the swing of things, set your hook variables the archaic way: store just one function rather than a list of functions. But that is optional.
• The variable lisp-indent-hook has been renamed to lisp-indent-function.
• The variable auto-fill-function has been renamed to auto-fill-hook.
• The blink-paren-function has been renamed to blink-paren-hook.
• The variable temp-buffer-show-function has been renamed to temp-buffer-show-hook.