anchor.diff:  ############################# Datatypes ####################################
   ############################################################################
   
  -    rule builtin_type:
  +    rule type_decl:
           typevar_item
  -        | TOKINTEGER | TOKBOOL | TOKSTRING | TOKREAL | TOKNAT | TOKACTION | TOKACTIONVALUE
  -
  -    rule type_decl:
  -        builtin_type
           | VAR [ LBRACKET NUM (COLON NUM)* RBRACKET ]
           | CLASSVAR typevar_item_or_var
   
  
positive.code: 
      rule goal:
          ( declaration_item
          | TOKPACKAGE VAR SEMICOLON
              ( declaration_item )*
              TOKENDPACKAGE [ COLON  VAR]
          )* ENDTOKEN
  
  %%
  
negative.code:         |    (TOKTAGGED term_single)+ [term_single]
          |    BUILTINVAR [ param_list ]
          |    term_single
          |    STR {{ return STR }}
          |    paren_expression
          |    LBRACE assign_rvalue ( COMMA assign_rvalue )* RBRACE
  