anchor.diff:      | base
       ;
   
  -getterSetterMethodReference
  -    : 'set' prim -> ^(SET_EXPR prim)
  -    | 'get' prim -> ^(GET_EXPR prim)
  -    ;
  -
   postfixOperator
       : '--' | '++'
       ;	
  
positive.code:     : '{' expressions? '}'
      -> ^(ENUM_LIST expressions?)
      ;
  
  primary
      : getterSetterMethodReference
      | prim
      //-> ^(PRIMARY prim)
      ;	
      
  prim
  options {backtrack=true;}
  /*
      : b=base 
  
negative.code: 
  NONEMPTY
      :   'nonempty'
      ;
  
  RETURN
  