"intensity" "to" exp /

         "character" "width" "to" exp /

         "blink" onoff /

        "italics" onff;

      onoff = "on" / "off";

      estab = "establish" buffername;

   LOGICAL SCREEN

      The screen is taken to be a square.  The coordinates are
      normalized from -1 to +1 on both axes.

      Associated with the screen is a position register, called
      PREG.  The register is a triple  where x and y 
      specify a point on the screen and r is a rotation in
      radians, counter clockwise, from the x-axis.

      The intensity, called INTENSITY, is a real number in the
      range from 0 to 1.  0 is black, 1 is as light as your
      display can go, and numbers in between specify the relative
      log of the intensity difference.

      Character frame size.

      Blink bit.

   BUFFER BUILDING

      The terminal nodes of semi-trees are either semi-tree names
      or display buffers.  A display buffer is a series of logical
      entities, called bufstuff.

      When the buffer is initilized, it is empty.  If no
      parameters are initially appended, those in effect at the
      end of the display of the last node in the semi-tree will be in
      effect for the display of this node.

      As the buffer is built, the logical entities are added to it.
      When it is established as a buffername, the buffer is
      closed, and further appends are prohibited.  It is only a
      buffername has been established that it may be used in a tree
      building statement.

   LOGICAL INPUT DEVICES

      Wand

      Joy Stick

      Keyboard

      Buttons

      Light Pens

      Mice

   AUDIO OUTPUT DEVICES

   .end


SAMPLE PROGRAMS

   Program to run display and keyboard as tty.

   to run NLS

      input part

      display part

         DEMAND MESSAGE;

         While LENGTH " O DO

            ITHCASE GETBYTE OF Begin

            ITHCASE GETBYTE OF %file area uipdate% BEGIN

               %literal area%

               %message area%

               %name area%

               %bug%

               %sequence specs%

               %filter specs%

               %format specs%