(defmacro make-help-screen (fname help-line help-text helped-map)
"Construct help-menu function name FNAME.
When invoked, FNAME shows HELP-LINE and reads a command using HELPED-MAP.
-If the command is the help character is requested, FNAME displays HELP-TEXT
+If the command is the help character, FNAME displays HELP-TEXT
and continues trying to read a command using HELPED-MAP.
When FNAME finally does get a command, it executes that command
and then returns."