Hook Changes

• Expanding an abbrev first runs the new hook pre-abbrev-expand-hook.
• The editor command loop runs the normal hook pre-command-hook before each command, and runs post-command-hook after each command.
• Auto-saving runs the new hook auto-save-hook before actually starting to save any files.
• The new variable revert-buffer-insert-file-contents-function holds a function that revert-buffer now uses to read in the contents of the reverted buffer--instead of calling insert-file-contents.
• The variable lisp-indent-hook has been renamed to lisp-indent-function.
• The variable auto-fill-hook has been renamed to auto-fill-function.
• The variable blink-paren-hook has been renamed to blink-paren-function.
• The variable temp-buffer-show-hook has been renamed to temp-buffer-show-function.
• The variable suspend-hook is now a normal hook. It used to be a special kind of hook; its value had to be a single function, and if the function returned a non-nil value, then suspension was inhibited.
• The new function add-hook provides a handy way to add a function to a hook variable. For example,

  (add-hook 'text-mode-hook 'my-text-hook-function)
  

  arranges to call my-text-hook-function when entering Text mode or related modes. add-hook takes an optional third argument which says to add the new hook function at the end of the list (normally, it goes at the beginning).