what is meaning of

[altair]

Hello!
Please what is the meaning of CurrentController and Frame in that macro:

sub letter_m 
   dim document as object 
   dim dispatcher as object 
   document  =ThisComponent.CurrentController.Frame 
   dispatcher = createUnoService("com.sun.star.frame.DispatchHelper") 
   dim args(0) as new com.sun.star.beans.PropertyValue 
   args1(0) .Name = "Text" 
   args1(0) .Value = "Value" 
   dispatcher.executeDispatch(document, " .uno:InsertText", "", 0, args1()) 
end sub