my $TG = Marpa::R2::Grammar->new({
        start=>'FILE', actions=>'ToyLang', default_action=>'swallow',
        unproductive_ok=>[qw(
            FILE
        )],
        rules=>[
            # A file contains a PROGRAM and zero or more SUBROUTINES.  The
            # subroutine definitions may precede and/or follow the program.
            [ FILE=>[qw( PROGRAM name stmt_list )], 'swallow' ], #PROGRAM FILE2)], ],
            [ FILE=>[qw( COMMENT FILE )], ], #stmt_list PROGRAM FILE2)], ],
#            [ FILE=>[qw( PROGRAM name stmt_list PROGRAM FILE2)], ],
#            [ FILE=>[qw( SUB name stmt_list sub FILE)], ],
#            [ FILE2=>[qw( SUB name stmt_list sub FILE2)], ],
         
            # A statement list consists of zero or more statements followed
            # by END.  We don't care whether or not there's an end of
            # statement marker before END.
            [ stmt_list=>[qw( END )],               'discard' ],
            [ stmt_list=>[qw( stmt stmt_list_2 )],  'first_on' ],
            [ stmt_list_2=>[qw( END )],             'discard' ],
            [ stmt_list_2=>[qw( OP_EOS END )] ],
            [ stmt_list_2=>[qw( OP_EOS stmt stmt_list_2 )], 'second_on' ],
         
#            [ stmt=>[qw( IF expr if_body )], ],
            [ stmt=>[qw( PRINT expr print_body )], ],
            [ stmt=>[qw( WHILE expr DO do_body )], ],
#            [ stmt=>[qw( DO do_body WHILE expr )], ],
            [ stmt=>[qw( name assop expr )],        'binary_op' ],
         
            [ do_body=>[qw( LOOP )], ],
            [ do_body=>[qw( stmt do_body_2 )],      'first_on' ],
            [ do_body_2=>[qw( LOOP )], ],
            [ do_body_2=>[qw( OP_EOS LOOP )],       'second_arg' ],
            [ do_body_2=>[qw( OP_EOS stmt do_body_2 )], 'second_arg' ],
         
            [ print_body=>[qw( OP_EOS )], ],
            [ print_body=>[qw( OP_COMMA expr print_body )], 'second_on' ],
         
            [ expr=>[qw( term )],                   'first_arg' ],
            [ expr=>[qw( expr logop expr )],        'binary_op' ],
         
            [ term=>[qw( term addop term )],        'binary_op' ],
            [ term=>[qw( factor )],                 'first_arg'],
         
            [ factor=>[qw( factor mulop factor )],  'binary_op'],
            [ factor=>[qw( name )],                 'first_arg'],
            [ factor=>[qw( number )],               'first_arg'],
            [ factor=>[qw( string )],               'first_arg'],
         
            [ addop=>[qw( OP_ADD )],                'first_arg'],
            [ addop=>[qw( OP_SUB )],                'first_arg'],
         
            [ assop=>[qw( OP_EQ )],                 'first_arg'],
            [ assop=>[qw( OP_EQADD )],              'first_arg'],
         
            [ logop=>[qw( OP_NEQ )],                'first_arg'],
         
            [ mulop=>[qw( OP_MUL )], ],
            [ mulop=>[qw( OP_DIV )], ],
        ],
});