-Disabling Commands
-------------------
-
- Disabling a command marks it as requiring confirmation before it can
-be executed. The purpose of disabling a command is to prevent
-beginning users from executing it by accident and being confused.
-
- The direct mechanism for disabling a command is to have a non-`nil'
-`disabled' property on the Lisp symbol for the command. These
-properties are normally set by the user's `.emacs' file with Lisp
-expressions such as:
-
- (put 'delete-region 'disabled t)
-
- If the value of the `disabled' property is a string, that string is
-included in the message printed when the command is used:
-
- (put 'delete-region 'disabled
- "Text deleted this way cannot be yanked back!\n")
-
- You can disable a command either by editing the `.emacs' file
-directly or with the command `M-x disable-command', which edits the
-`.emacs' file for you. *Note Init File::.
-
- When you attempt to invoke a disabled command interactively in Emacs,
-a window is displayed containing the command's name, its documentation,
-and some instructions on what to do next; then Emacs asks for input
-saying whether to execute the command as requested, enable it and
-execute, or cancel it. If you decide to enable the command, you are
-asked whether to do this permanently or just for the current session.
-Enabling permanently works by automatically editing your `.emacs' file.
-You can use `M-x enable-command' at any time to enable any command
-permanently.
-
- Whether a command is disabled is independent of what key is used to
-invoke it; it also applies if the command is invoked using `M-x'.
-Disabling a command has no effect on calling it as a function from Lisp
-programs.
-
-\1f
-File: xemacs.info, Node: Syntax, Next: Init File, Prev: Key Bindings, Up: Customization
-
-The Syntax Table
-================
-
- All the Emacs commands which parse words or balance parentheses are
-controlled by the "syntax table". The syntax table specifies which
-characters are opening delimiters, which are parts of words, which are
-string quotes, and so on. Actually, each major mode has its own syntax
-table (though sometimes related major modes use the same one) which it
-installs in each buffer that uses that major mode. The syntax table
-installed in the current buffer is the one that all commands use, so we
-call it "the" syntax table. A syntax table is a Lisp object, a vector
-of length 256 whose elements are numbers.
-
-* Menu:
-
-* Entry: Syntax Entry. What the syntax table records for each character.
-* Change: Syntax Change. How to change the information.
-
-\1f
-File: xemacs.info, Node: Syntax Entry, Next: Syntax Change, Up: Syntax
-
-Information About Each Character
---------------------------------
-
- The syntax table entry for a character is a number that encodes six
-pieces of information:
-
- * The syntactic class of the character, represented as a small
- integer
-
- * The matching delimiter, for delimiter characters only (the
- matching delimiter of `(' is `)', and vice versa)
-
- * A flag saying whether the character is the first character of a
- two-character comment starting sequence
-
- * A flag saying whether the character is the second character of a
- two-character comment starting sequence
-
- * A flag saying whether the character is the first character of a
- two-character comment ending sequence
-
- * A flag saying whether the character is the second character of a
- two-character comment ending sequence
-
- The syntactic classes are stored internally as small integers, but
-are usually described to or by the user with characters. For example,
-`(' is used to specify the syntactic class of opening delimiters. Here
-is a table of syntactic classes, with the characters that specify them.
-
-` '
- The class of whitespace characters.
-
-`w'
- The class of word-constituent characters.
-
-`_'
- The class of characters that are part of symbol names but not
- words. This class is represented by `_' because the character `_'
- has this class in both C and Lisp.
-
-`.'
- The class of punctuation characters that do not fit into any other
- special class.
-
-`('
- The class of opening delimiters.
-
-`)'
- The class of closing delimiters.
-
-`''
- The class of expression-adhering characters. These characters are
- part of a symbol if found within or adjacent to one, and are part
- of a following expression if immediately preceding one, but are
- like whitespace if surrounded by whitespace.
-
-`"'
- The class of string-quote characters. They match each other in
- pairs, and the characters within the pair all lose their syntactic
- significance except for the `\' and `/' classes of escape
- characters, which can be used to include a string-quote inside the
- string.
-
-`$'
- The class of self-matching delimiters. This is intended for TeX's
- `$', which is used both to enter and leave math mode. Thus, a
- pair of matching `$' characters surround each piece of math mode
- TeX input. A pair of adjacent `$' characters act like a single
- one for purposes of matching.
-
-`/'
- The class of escape characters that always just deny the following
- character its special syntactic significance. The character after
- one of these escapes is always treated as alphabetic.
-
-`\'
- The class of C-style escape characters. In practice, these are
- treated just like `/'-class characters, because the extra
- possibilities for C escapes (such as being followed by digits)
- have no effect on where the containing expression ends.
-
-`<'
- The class of comment-starting characters. Only single-character
- comment starters (such as `;' in Lisp mode) are represented this
- way.
-
-`>'
- The class of comment-ending characters. Newline has this syntax in
- Lisp mode.
-
- The characters flagged as part of two-character comment delimiters
-can have other syntactic functions most of the time. For example, `/'
-and `*' in C code, when found separately, have nothing to do with
-comments. The comment-delimiter significance overrides when the pair of
-characters occur together in the proper order. Only the list and sexp
-commands use the syntax table to find comments; the commands
-specifically for comments have other variables that tell them where to
-find comments. Moreover, the list and sexp commands notice comments
-only if `parse-sexp-ignore-comments' is non-`nil'. This variable is set
-to `nil' in modes where comment-terminator sequences are liable to
-appear where there is no comment, for example, in Lisp mode where the
-comment terminator is a newline but not every newline ends a comment.
-
-\1f
-File: xemacs.info, Node: Syntax Change, Prev: Syntax Entry, Up: Syntax
-
-Altering Syntax Information
----------------------------
-
- It is possible to alter a character's syntax table entry by storing
-a new number in the appropriate element of the syntax table, but it
-would be hard to determine what number to use. Emacs therefore
-provides a command that allows you to specify the syntactic properties
-of a character in a convenient way.
-
- `M-x modify-syntax-entry' is the command to change a character's
-syntax. It can be used interactively and is also used by major modes
-to initialize their own syntax tables. Its first argument is the
-character to change. The second argument is a string that specifies the
-new syntax. When called from Lisp code, there is a third, optional
-argument, which specifies the syntax table in which to make the change.
-If not supplied, or if this command is called interactively, the third
-argument defaults to the current buffer's syntax table.
-
- 1. The first character in the string specifies the syntactic class.
- It is one of the characters in the previous table (*note Syntax
- Entry::.).
-
- 2. The second character is the matching delimiter. For a character
- that is not an opening or closing delimiter, this should be a
- space, and may be omitted if no following characters are needed.
-
- 3. The remaining characters are flags. The flag characters allowed
- are:
-
- `1'
- Flag this character as the first of a two-character comment
- starting sequence.
-
- `2'
- Flag this character as the second of a two-character comment
- starting sequence.
-
- `3'
- Flag this character as the first of a two-character comment
- ending sequence.
-
- `4'
- Flag this character as the second of a two-character comment
- ending sequence.
-
- Use `C-h s' (`describe-syntax') to display a description of the
-contents of the current syntax table. The description of each
-character includes both the string you have to pass to
-`modify-syntax-entry' to set up that character's current syntax, and
-some English to explain that string if necessary.
-
-\1f
-File: xemacs.info, Node: Init File, Next: Audible Bell, Prev: Syntax, Up: Customization
-
-The Init File, .emacs
-=====================
-
- When you start Emacs, it normally loads the file `.emacs' in your
-home directory. This file, if it exists, should contain Lisp code. It
-is called your initialization file or "init file". Use the command
-line switch `-q' to tell Emacs whether to load an init file (*note
-Entering Emacs::.). Use the command line switch `-user-init-file'
-(*note Command Switches::.) to tell Emacs to load a different file
-instead of `~/.emacs'.
-
- When the `.emacs' file is read, the variable `user-init-file' says
-which init file was loaded.
-
- At some sites there is a "default init file", which is the library
-named `default.el', found via the standard search path for libraries.
-The Emacs distribution contains no such library; your site may create
-one for local customizations. If this library exists, it is loaded
-whenever you start Emacs. But your init file, if any, is loaded first;
-if it sets `inhibit-default-init' non-`nil', then `default' is not
-loaded.
-
- If you have a large amount of code in your `.emacs' file, you should
-move it into another file named `SOMETHING.el', byte-compile it (*note
-Lisp Libraries::.), and load that file from your `.emacs' file using
-`load'.
-
-* Menu:
-
-* Init Syntax:: Syntax of constants in Emacs Lisp.
-* Init Examples:: How to do some things with an init file.
-* Terminal Init:: Each terminal type can have an init file.
+Recursive Editing Levels
+========================
+
+ A "recursive edit" is a situation in which you are using XEmacs
+commands to perform arbitrary editing while in the middle of another
+XEmacs command. For example, when you type `C-r' inside a
+`query-replace', you enter a recursive edit in which you can change the
+current buffer. When you exit from the recursive edit, you go back to
+the `query-replace'.
+
+ "Exiting" a recursive edit means returning to the unfinished
+command, which continues execution. For example, exiting the recursive
+edit requested by `C-r' in `query-replace' causes query replacing to
+resume. Exiting is done with `C-M-c' (`exit-recursive-edit').
+
+ You can also "abort" a recursive edit. This is like exiting, but
+also quits the unfinished command immediately. Use the command `C-]'
+(`abort-recursive-edit') for this. *Note Quitting::.
+
+ The mode line shows you when you are in a recursive edit by
+displaying square brackets around the parentheses that always surround
+the major and minor mode names. Every window's mode line shows the
+square brackets, since XEmacs as a whole, rather than any particular
+buffer, is in a recursive edit.
+
+ It is possible to be in recursive edits within recursive edits. For
+example, after typing `C-r' in a `query-replace', you might type a
+command that entered the debugger. In such a case, two or more sets of
+square brackets appear in the mode line(s). Exiting the inner
+recursive edit (here with the debugger `c' command) resumes the
+query-replace command where it called the debugger. After the end of
+the query-replace command, you would be able to exit the first
+recursive edit. Aborting exits only one level of recursive edit; it
+returns to the command level of the previous recursive edit. You can
+then abort that one as well.
+
+ The command `M-x top-level' aborts all levels of recursive edits,
+returning immediately to the top level command reader.
+
+ The text you edit inside the recursive edit need not be the same text
+that you were editing at top level. If the command that invokes the
+recursive edit selects a different buffer first, that is the buffer you
+will edit recursively. You can switch buffers within the recursive edit
+in the normal manner (as long as the buffer-switching keys have not been
+rebound). While you could theoretically do the rest of your editing
+inside the recursive edit, including visiting files, this could have
+surprising effects (such as stack overflow) from time to time. It is
+best if you always exit or abort a recursive edit when you no longer
+need it.
+
+ In general, XEmacs tries to avoid using recursive edits. It is
+usually preferable to allow users to switch among the possible editing
+modes in any order they like. With recursive edits, the only way to get
+to another state is to go "back" to the state that the recursive edit
+was invoked from.