Provides the way of window creation the properties of this window are appended --in case of '-class' directly-- afterward.
Example 3.48. ::vgcode::dump-widget using instantiate
... set classname \ [substitutep $classname] debug stdout "Now the item is created from : $classname as $ta_name" append output \ [dumper::instantiate $classname $ta_name "converted from \ [winfo class $target]"]