anchor.diff:      rule dep_item:
           VAR TOKDETERMINES VAR
   
  -    rule typeclass_statement:
  -        TOKTYPECLASS typevar_item
  -        [ TOKDEPENDENCIES LPAREN dep_item (COMMA dep_item)* RPAREN ]
  -        SEMICOLON
  -        ( function_declaration
  -        | module_declaration
  -        )*
  -        TOKENDTYPECLASS [ COLON VAR ]
  -
       rule goal:
  -        (top_level_statement)* ENDTOKEN
  +        ( package_declaration_item
  +        | package_declaration
  +        )* ENDTOKEN
   
   %%
   import string
  
positive.code:             TOKENDINTERFACE [ COLON VAR ]
          )
  
      rule match_arg:
          DOT ( term<<[]>> | STAR )
          | match_brace
  
negative.code:         ( EQUAL | LARROW ) assign_value SEMICOLON
  
      rule if_statement:
          TOKIF paren_expression
             single_statement [ TOKELSE single_statement ]
  
      rule rule_statement:
          TOKRULE VAR [paren_expression] SEMICOLON
          statement_list
          TOKENDRULE [ COLON  VAR ]
  
  