on-insert (augmentable only) in text%

Called before items are inserted into the editor, after can-insert? is called to verify that the insertion is ok. The after-insert method is guaranteed to be called after the insert has completed.

The editor is internally locked for writing during a call to this method (see also Locks). Use after-insert to modify the editor, if necessary.

See also on-edit-sequence.

• (send a-text on-insert start len) -> void
     start : exact non-negative integer
     len : exact non-negative integer

  The start argument specifies the position of the insert. The len argument specifies the total length (in positions) of the items to be inserted.