解析与提振精神逃脱串 [英] Parsing escaped strings with boost spirit
问题描述
I'm与精神2.4工作,我会想解析这样的结构:
I´m working with Spirit 2.4 and I'd want to parse a structure like this:
文字{text_field};
Text{text_field};
问题的关键是,在text_field是一个转义字符串与符号'{','}'和'\\'。
我想创建一个解析器使用这个气。我一直在想这样的:
The point is that in text_field is a escaped string with the symbols '{', '}' and '\'. I would like to create a parser for this using qi. I've been trying this:
using boost::spirit::standard::char_;
using boost::spirit::standard::string;
using qi::lexeme;
using qi::lit;
qi::rule< IteratorT, std::string(), ascii::space_type > text;
qi::rule< IteratorT, std::string(), ascii::space_type > content;
qi::rule< IteratorT, std::string(), ascii::space_type > escChar;
text %=
lit( "Text" ) >> '{' >>
content >>
"};"
;
content %= lexeme[ +( +(char_ - ( lit( '\\' ) | '}' ) ) >> escChar ) ];
escChar %= string( "\\\\" )
| string( "\\{" )
| string( "\\}" );
但不编译。任何想法?
But doesn't even compile. Any idea?
推荐答案
您的语法可以写成:
qi::rule< IteratorT, std::string(), ascii::space_type > text;
qi::rule< IteratorT, std::string() > content;
qi::rule< IteratorT, char() > escChar;
text = "Text{" >> content >> "};";
content = +(~char_('}') | escChar);
escChar = '\\' >> char_("\\{}");
即。
-
的文本的是
文本{
之后的内容,然后按}
text is
Text{
followed by content followed by}
的内容的是至少有一个实例
或者是字符(但没有}
)或
一个escChar
content is at least one instance of
either a character (but no }
) or
an escChar
的 escChar 的是单个转义 \\\\
, {
或}
请注意,在 escChar 的规则现在返回单个字符,并丢弃逃逸 \\\\
。我不知道如果这就是你所需要的。此外,我删除了队长的的内容的和的 escChar 的规则,允许离开关语义[]
(没有队长的规则就像一个隐含的语义)。
Note, the escChar rule now returns a single character and discards the escaping \\
. I'm not sure if that's what you need. Additionally, I removed the skipper for the content and escChar rules, which allows to leave off the lexeme[]
(a rule without skipper acts like an implicit lexeme).
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