help.txt output-handler.txt                                 

                               Output Handler

The state in editor has an entry ::output-handler. It is supposed to 
reference a datastructure of the following form:

    {:printer function: [buffer] -> nil
     :invalidate function: [] -> nil
     :dimensions function: [] -> {:rows int :cols int}

The :printer value is a function able to "print" a buffer on the output 
device (tty screen, JFrame, HTML, etc.)

The :invalidate value is a function taking no parameters. It is called when 
the editor wants to signal that a complete redraw of the screen should be 

The :dimensions value is a function return a map with :rows and :cols. It 
will usually be the output device who knows the dimensions of the print area.