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Menus

Menus contain pointers to subordinate nodes.(6) In Info, you use menus to go to such nodes. Menus have no effect in printed manuals and do not appear in them.

By convention, a menu is put at the end of a node since a reader who uses the menu may not see text that follows it. Furthermore, a node that has a menu should not contain much text. If you have a lot of text and a menu, move most of the text into a new subnode--all but a few lines. Otherwise, a reader with a terminal that displays only a few lines may miss the menu and its associated text. As a practical matter, you should locate a menu within 20 lines of the beginning of the node.

The short text before a menu may look awkward in a printed manual. To avoid this, you can write a menu near the beginning of its node and follow the menu by an @node line, and then an @heading line located within @ifinfo and @end ifinfo. This way, the menu, @node line, and title appear only in the Info file, not the printed document.

For example, the preceding two paragraphs follow an Info-only menu, @node line, and heading, and look like this:

@menu
* Menu Location::             Put a menu in a short node.
* Writing a Menu::            What is a menu?
* Menu Parts::                A menu entry has three parts.
* Less Cluttered Menu Entry:: Two part menu entry.
* Menu Example::              Two and three part entries.
* Other Info Files::          How to refer to a different
                                Info file.
@end menu

@node Menu Location, Writing a Menu, , Menus
@ifinfo
@heading Menus Need Short Nodes
@end ifinfo

The Texinfo file for this document contains more than a dozen examples of this procedure. One is at the beginning of this chapter; another is at the beginning of section Cross References.

Writing a Menu

A menu consists of an @menu command on a line by itself followed by menu entry lines or menu comment lines and then by an @end menu command on a line by itself.

A menu looks like this:

@menu
Larger Units of Text

* Files::                       All about handling files.
* Multiples: Buffers.           Multiple buffers; editing
                                  several files at once.
@end menu

In a menu, every line that begins with an `* ' is a menu entry. (Note the space after the asterisk.) A line that does not start with an `* ' may also appear in a menu. Such a line is not a menu entry but is a menu comment line that appears in the Info file. In the example above, the line `Larger Units of Text' is a menu comment line; the two lines starting with `* ' are menu entries. Space characters in a menu are preserved as-is; this allows you to format the menu as you wish.

The Parts of a Menu

A menu entry has three parts, only the second of which is required:

  1. The menu entry name (optional).
  2. The name of the node (required).
  3. A description of the item (optional).

The template for a menu entry looks like this:

* menu-entry-name: node-name.   description

Follow the menu entry name with a single colon and follow the node name with tab, comma, period, or newline.

In Info, a user selects a node with the m (Info-menu) command. The menu entry name is what the user types after the m command.

The third part of a menu entry is a descriptive phrase or sentence. Menu entry names and node names are often short; the description explains to the reader what the node is about. A useful description complements the node name rather than repeats it. The description, which is optional, can spread over two or more lines; if it does, some authors prefer to indent the second line while others prefer to align it with the first (and all others). It's up to you.

Less Cluttered Menu Entry

When the menu entry name and node name are the same, you can write the name immediately after the asterisk and space at the beginning of the line and follow the name with two colons.

For example, write

* Name::                                    description

instead of

* Name: Name.                               description

You should use the node name for the menu entry name whenever possible, since it reduces visual clutter in the menu.

A Menu Example

A menu looks like this in Texinfo:

@menu
* menu entry name: Node name.   A short description.
* Node name::                   This form is preferred.
@end menu

This produces:

* menu:

* menu entry name: Node name.   A short description.
* Node name::                   This form is preferred.

Here is an example as you might see it in a Texinfo file:

@menu
Larger Units of Text

* Files::                       All about handling files.
* Multiples: Buffers.           Multiple buffers; editing
                                  several files at once.
@end menu

This produces:

* menu:
Larger Units of Text

* Files::                       All about handling files.
* Multiples: Buffers.           Multiple buffers; editing
                                  several files at once.

In this example, the menu has two entries. `Files' is both a menu entry name and the name of the node referred to by that name. `Multiples' is the menu entry name; it refers to the node named `Buffers'. The line `Larger Units of Text' is a comment; it appears in the menu, but is not an entry.

Since no file name is specified with either `Files' or `Buffers', they must be the names of nodes in the same Info file (see section Referring to Other Info Files).

Referring to Other Info Files

You can create a menu entry that enables a reader in Info to go to a node in another Info file by writing the file name in parentheses just before the node name. In this case, you should use the three-part menu entry format, which saves the reader from having to type the file name.

The format looks like this:

@menu
* first-entry-name:(filename)nodename.     description
* second-entry-name:(filename)second-node. description
@end menu

For example, to refer directly to the `Outlining' and `Rebinding' nodes in the Emacs Manual, you would write a menu like this:

@menu
* Outlining: (emacs)Outline Mode. The major mode for
                                  editing outlines.
* Rebinding: (emacs)Rebinding.    How to redefine the
                                  meaning of a key.
@end menu

If you do not list the node name, but only name the file, then Info presumes that you are referring to the `Top' node.

The `dir' file that contains the main menu for Info has menu entries that list only file names. These take you directly to the `Top' nodes of each Info document. (See section Installing an Info File.)

For example:

* Info: (info).         Documentation browsing system.
* Emacs: (emacs).       The extensible, self-documenting
                        text editor.

(The `dir' top level directory for the Info system is an Info file, not a Texinfo file, but a menu entry looks the same in both types of file.)

The GNU Emacs Texinfo mode menu updating commands only work with nodes within the current buffer, so you cannot use them to create menus that refer to other files. You must write such menus by hand.


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