open-output-text-editor in Editors

• (open-output-text-editor text-editor start-position special-filter port-name) -> output-port
     text-editor : text% object
     start-position = 'end : exact non-negative integer or 'end
   special-filter = values : a procedure of one argument: a value
     port-name = text-editor : value

  Creates an output port that delivers its content to text-editor. The content is written to text-editor starting at the position start-position, where 'end indicates that output should start at the text editor's current end position.

  If special-filter is provided, it is applied to any value written to the port with write-special, and the result is inserted in its place. If a special value is a snip% object, it is inserted into the editor. Otherwise, the special value is displayed into the editor.

  If line counting is enabled for the resulting output port, then the port will report the line, offset from the line's start, and position within the editor at which the port writes data.