spork/getline/default-autocomplete-context

    function
    /usr/local/lib/janet/spork/getline.janet on line 22, column 1

    (default-autocomplete-context buf pos)

    Given a buffer and a cursor position, extract a string that will be 
    used as context for autocompletion. Return a position and substring 
    from the buffer to use for autocompletion.