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