perl – 使用Marpa进行不正确的标记化

use strict;
use warnings;
use Marpa::R2;

my $grammar = Marpa::R2::Scanless::G->new(
    {
        source => (<<'END_OF_SOURCE'),:default ::= action => ::array
            :start ::= Start

            Start  ::= Child DoubleColon Token

            DoubleColon ~ '::'
            Child ~ 'child'
            Token ~
                word
                | word ':' word
            word ~ [w]+

END_OF_SOURCE
    }
);
my $reader = Marpa::R2::Scanless::R->new(
    {
        grammar => $grammar,trace_terminals => 1,}
);

my $input = 'child::book';
$reader->read($input);

此脚本打印以下内容：

Registering character U+0063 as symbol 10: [[w]]
Registering character U+0063 as symbol 3: [[c]]
Registering character U+0068 as symbol 10: [[w]]
Registering character U+0068 as symbol 4: [[h]]
Registering character U+0069 as symbol 10: [[w]]
Registering character U+0069 as symbol 5: [[i]]
Registering character U+006c as symbol 10: [[w]]
Registering character U+006c as symbol 6: [[l]]
Registering character U+0064 as symbol 10: [[w]]
Registering character U+0064 as symbol 7: [[d]]
Registering character U+003a as symbol 1: [[:]]
Rejected lexeme @0-5: Token; value="child"
Accepted lexeme @0-5: Child; value="child"
Registering character U+0062 as symbol 10: [[w]]
Error in SLIF G1 read: No lexeme found at position 6
* String before error: child::
* The error  was at line 1,column 8,and at character 0x0062 'b',...
* here: book

我希望输入被标记为[Child] [DoubleColon] [word].如终端跟踪显示,只读取和处理一个冒号字符.似乎它试图将字符串的开头标记为[word] [‘：’] [word]并且在中途失败.如果删除语法的第10行(| word’：’word),将不再抛出错误.

我尝试为DoubleColon创建优先级(：lexeme~< DoubleColon> priority> 1),但这不起作用.有人能告诉我该怎么做才能使这个语法正确解析输入字符串吗？它仍然需要能够解析child :: ns：book等.