anchor.diff:    ;
   
   range_constraint
  -  : RANGE range
  +  : RANGE range_decl
     ;
   
   record_nature_definition
  
positive.code:   : quantity_list COLON name
    ;
  
  range
    : explicit_range
    | name
    ;
  
negative.code:   ;
  
  discrete_range
    : range_decl
    | subtype_indication
    ;
  
  