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 Menus and the M command

   With only the "N"  and "P" commands for  moving between nodes,  nodes
 are  restricted  to  a  linear  sequence.   Menus  allow  a   branching
 structure.  A menu is  a list of  other nodes you can  move to.  It  is
 actually just part of the text of the node formatted specially so  that
 INFO can interpret it.  The beginning of a menu is always identified by
 a line which starts with "* Menu:".  A node contains a menu if and only
 if it has a line  in it which starts that  way.  The only menu you  can
 use at any moment is the one in the node you are in.  To use a menu  in
 any other node, you must move to that node first.

   After the  start  of the  menu,  each line  that  starts with  a  "*"
 identifies one subtopic.  The  line will usually  contain a brief  name
 for the subtopic (followed by a ":"),  the name of the node that  talks
 about that subtopic,  and optionally  some further  description of  the
 subtopic.  Lines  in the  menu that  don't  start with  a "*"  have  no
 special meaning - they are only  for the human reader's benefit and  do
 not define additional subtopics.  Here is an example:
 * Foo: FOO's Node      This tells about FOO
 The subtopic name is Foo, and  the node describing it is "FOO's  Node".
 The rest of the line is just for the reader's information.

   When you use  a menu to  go to another  node (in a  way that will  be
 described soon), what you specify is the subtopic name, the first thing
 in the menu line.   INFO uses it  to find the  menu line, extracts  the
 node name from it,  and goes to  that node.  The  reason that there  is
 both a subtopic  name and a  node name is  that the node  name must  be
 meaningful to the computer and may  therefore have to be ugly  looking.
 The subtopic name can be chosen just  to be convenient for the user  to
 specify.  Often the node name is convenient for the user to specify and
 so  both  it  and  the  subtopic  name  are  the  same.   There  is  an
 abbreviation for this:
 * Foo::   This tells about FOO
 This means that the subtopic name and node name are the same; they  are
 both "Foo".

 >> Now use Spaces to find the menu in this node, then come back to  the
 front with a "B".  As you see, a menu is actually visible in its  node.
 If you can't  find a menu  in a node  by looking at  it, then the  node
 doesn't have a menu.  The only menu you can use is the one (if any)  in
 the current node.  To use a menu in another node, you must first get to
 that node somehow.

   The command to go  to one of the  subnodes is "M" -  but DON'T DO  IT
 YET!  Before you use  "M", you must  understand the difference  between
 commands and arguments.  So far, you have learned several commands that
 do not need  arguments.  When you  type one, INFO  processes it and  is
 instantly ready for another command.  The "M" command is different:  it
 is incomplete without the  NAME OF THE SUBTOPIC.   Once you have  typed
 "M", INFO tries to read the name.

   Now look for the text "INFO documentation reader" near the bottom  of
 the screen.  As long as that text is there, INFO is awaiting a command.
 When that line says something else, INFO is trying to read the ARGUMENT
 to a command.  At  such times, commands won't  work, because INFO  will
 try to use them as the argument.  You must either type the argument and
 finish the  command  you  started,  or type  Control-G  to  cancel  the
 command.  When you have done one of those things, the line will  change
 back to "INFO documentation reader".

   The command to go to a subnode via  a menu is "M".  When you type  an
 "M", the top of the menu will appear on the screen if it wasn't already
 visible.  If the menu doesn't all fit on the screen, you can use  Space
 and Caret as usual to move around  in it.  When you have decided  which
 subtopic  to  look  at,  type  the  subtopic's  name,  ended  by  a  CR
 (Carriage-Return).   You  can  abbreviate  the  topic  name.   If   the
 abbreviation is not unique, the  first matching topic is chosen.   Some
 menus will put the shortest  possible abbreviation for each topic  name
 in capital letters,  so you can  see how  much you need  to type.   You
 should not put  any spaces  at the  end, or  inside of  the item  name,
 except for one space where a space appears in the item in the menu.

 >>  Now type just an "M" and see what happens:

   Here is a menu to give you a chance to practice.

 * Menu:           The menu starts here.  Type a space if you need to.

 This menu gives you three ways of going to one place, Help-FOO.

 * Foo: Help-FOO        A node you can visit for fun
 * Bar: Help-FOO        Strange!  two ways to get to the same place.
 * Help-FOO::           And yet another!

   Now you are "inside" an "M" command.  Commands can't be used now; the
 next thing you will type  must be the name  of a subtopic.  Notice  how
 "INFO documentation reader" has changed  to "INFO, awaiting Menu  item"
 to tell you what you should type next (find this on the screen).

 >> Type a question-mark and see what you get.

   You can change your mind about doing the "M" by typing a Rubout.
 >> Try that now;  notice the "awaiting Menu item" change back
 >> Then type another "M".

 >> Now type "Foo", the item name.  Don't type CR yet.

   While you are typing the item name, you can use the Rubout  character
 to cancel one character at a time if you make a mistake.
 >> Type one  to cancel the  last "O".   You could type  another "O"  to
 replace it.  You don't have to, since "FO" is a valid abbreviation.
 >> Now you are ready to go.  Type a CR.

   After visiting FOO-Node, you should return here.

 >> Type "N" to see more commands.