import javax.swing.undo.UndoManager;

svoid clearTextComponentUndoList(JTextComponent c) swing {
  ifclass RSyntaxTextArea
    if (c cast RSyntaxTextArea)
      ret with c.discardAllEdits();
  endif
  
  UndoManager undo = cast metaGet(c, "UndoManager");
  if (undo != null)
    undo.discardAllEdits();
}