Ifacedata$ ()

   Synopsis:
      Returns the first item of additional data provided by the interface when
         it fired   

   Notes:
      The interface notification list contains all the notifications received,
         and not yet processed, as the result of an earlier SETTRIG, SETALIAS,
         SETMACRO, SETTIMER or SETHOOK statement.
      This function operates on the current notification (usually the first one;
         see the help for SKIPIFACE).

      The Ifacetext$ () function returns whatever caused the interface to fire.
         Some interfaces provide additional data when they fire, but some do
         not. The help for Ifacedefined () contains more information about this.
      This function returns the first piece of additional data, if any. It
         returns exactly the same value as Ifaceselect$ (1).

      After a SETTRIG or SETALIAS statement, a pattern is matched against some
         text. Matching the pattern can generate some group substrings, if the
         pattern itself specifies one or more groups.
      In both cases, this function returns the first substring (or an empty
         string, if the pattern contained no groups).
         
      After a SETMACRO statement, always returns an empty string.

      Timers can have a stimulus set to a clock time, in the form "HH:MM" (the
        timer fires once per day), or "99::MM" (the timer fires once per hour,
        at MM minutes past the hour). If so, after a SETTIMER statement this
        function returns that clock time (as a string). If not, this function
        returns the time at which the timer was due to fire (which will be
        equal to, or slightly earlier than, the time at which the timer actually
        fired, which is the value returned by Ifacetext () ).
        
      Some hook events generate an one or two additional items of data. If so,
         after a SETHOOK statement, this function returns the first item of
         data, or an empty string if no additional data was available.
      (To retrieve the second item of data, when required, you can use the
         Ifaceselect () function.)
         
   Compatibility:
      Since Axbasic v1.4
