This tests the pass by name some more, seeing if
we can assign to a complete reference that
we pass in (bangstartII) or, for the truly insane
pass in a reference that a property is assumed
within (BangstartII)

Note that you wont see anything rendered, but
SetBangStart will output to stdout

#macro( bangstart $a)
  #set( $a.BangStart = 4 ) 
#end

#macro( bangstartII $a)
  #set( $a = 5 ) 
#end

#macro( bar $b )
  $b.bang() 
#end

#bangstart( $provider )
#bangstartII( $provider.BangStart )