Appendix A Emacs 22 Antinews

For those users who live backwards in time, here is information about downgrading to Emacs version 22.3. We hope you will enjoy the greater simplicity that results from the absence of many Emacs 23.3 features.

A.1 Old Lisp Features in Emacs 22

• The internal character representation used by Emacs is not longer based on Unicode. In this representation, called emacs-mule, each character belongs to one and only one script. Emacs makes no attempt to distinguish between “similar” characters occurring in different scripts.
• The ^ interactive spec code, the function handle-shift-selection, and the variable this-command-keys-shift-translated have all been removed. Shift-translated keys are no longer treated specially, making Emacs' handling of keybindings much more consistent.
• Temporarily-active regions are not created by giving the variable transient-mark-mode values of the form (only . oldvar). We instead use a more complicated scheme: setting transient-mark-mode to only enables Transient Mark mode for the following command only, during which the value of transient-mark-mode is set to identity; if it is still identity at the end of the command, Transient Mark mode is disabled.
• Many minibuffer functions, such as read-file-name and minibuffer-complete, have been rewritten in C for greater speed. The completion code has been considerably simplified; the completion style can no longer be changed via completion-styles-alist, and completing-read no longer recognizes the special values confirm-only and confirm-after-completion for its require-match argument.
• Emacs no longer supports explicitly-numbered groups in regular expressions.
• The permanent-local-hook function property has no special meaning.
• The functionp function now returns t for special forms.
• The interactive-form symbol property has no special meaning. Once you supply a function with an interactive form, the only way to change it is to redefine the function.
• The ignore-errors macro has been moved into the cl package.
• Variables can now be both buffer-local and frame-local; buffer-local bindings take precedence over frame-local bindings.
• Faces can no longer be remapped.
• Lisp programs now specify fonts by their names, which are strings following the XLFD (X logical font descriptor) format. Fonts are no longer represented using a special set of “font” data types. The various functions that act on these data types, such as fontp, font-spec, and list-fonts, have all been deleted.
• Emacs does not recognize the FontBackend X resource and the font-backend frame parameter. On the X Window System, fonts are always drawn using the X core font driver.
• Display terminals are no longer represented using a “terminal” data type; this is not necessary, because we have removed the ability to display on graphical and text-only terminals simultaneously. For the same reason, the window-system variable is no longer frame-local, and the window-system function has been removed.
• The functions list-system-processes and process-attributes have been removed. To get information about system processes, call an external program, such as ps.
• The function locate-user-emacs-file and the variable user-emacs-directory have been removed. Instead, use hard-coded values pointing to ~/.emacs.d.
• vertical-motion can no longer be told to move to a specific column; it always puts point on the first column of a line.
• Windows no longer have parameters.
• The display-buffer function has been rewritten in C. Its window-splitting heuristics are a little less sophisticated, and a little less documented. Window-splitting is handled internally, instead of using split-window-preferred-function (which has been removed). Windows are never split horizontally; the variable split-width-threshold has been removed.
• The mode-name variable now accepts only string values, and cannot take the form of a mode-line construct.
• The behavior of map-char-table has changed. It calls the mapping function for every single character in the table, instead of using cons cells to represent contiguous character code ranges.
• Several keymaps have been eliminated: input-decode-map, local-function-key-map, search-map, multi-query-replace-map, and minibuffer-local-shell-command-map.
• Many functions have been removed, including: buffer-swap-text, emacs-init-time, emacs-uptime, use-region-p, region-active-p, start-file-process, process-lines, image-refresh, match-substitute-replacement, word-search-forward-lax, and word-search-backward-lax.
• Many variables have been removed, including read-circle, after-init-time and before-init-time, generate-autoload-cookie, file-local-variables-alist, replace-search-function and replace-re-search-function, inhibit-changing-match-data, wrap-prefix, and line-prefix,