anchor.diff:      rule param_list:
           LPAREN [ assign_value (COMMA assign_value)* ] RPAREN
   
  -    rule variable_assignment_or_call:
  -        term<<[]>>
  -        ( EQUAL | LEQ ) assign_value SEMICOLON
  -
  -    rule function_header:
  +    rule function_declaration:
           FUNCTION
           [
               ( Type_sitem
  
positive.code:         # datatype might not be present
          Type_nitem [ VAR ] ( EQUAL | LEQ ) assign_value
  
      rule for_statement:
          TOKFOR LPAREN
              for_decl_item (COMMA for_decl_item)* SEMICOLON
              assign_value SEMICOLON
              variable_assignment ( COMMA variable_assignment )* RPAREN
          single_statement
  
      rule while_statement:
          TOKWHILE LPAREN expression RPAREN
          ( action_statement
          | seq_statement
          | group_statement
          | VAR SEMICOLON
          )
  
      rule group_statement:
          BEGIN
          statement_list
  
negative.code:         ]
          [function_name]
          [ argument_list ]
          [ provisos_clause ]
          ( EQUAL assign_value SEMICOLON
          | SEMICOLON
              [
  