提取在括号和单引号之间使用单引号引起来的字符串 [英] extract a string with single quotes between parenthesis and single quote

问题描述

我有以下代码:

  #include <iostream>
#include <regex>

using namespace std;

int main()
{
  string s;

      s = "server ('m1.labs.terad  ata.com') username ('us er5') password('user)5') dbname ('def\\ault')";

    regex re("(\'(.*?)\'\)");
    sregex_token_iterator i(s.begin(), s.end(), re, 1);
   sregex_token_iterator j;

    unsigned count = 0;
    while(i != j)
      {
        cout <<*i<< endl;
        count++;
        i++;
      }
    cout << "There were " << count << " tokens found." << endl;

  return 0;
}

上面的正则表达式用于提取单引号之间的所有内容.

the regex above is meant to extract everything between the single quotes.

但是我如何制作正则表达式，以便它能够提取转义的单引号(示例用户名(用户"5")应提取为用户5".

But how can I make the regex so that it is able to extract escaped single quotes (example username (user''5) should be extracted as 'user'5'.

先谢谢了.我真的需要帮助.已经尝试了很多天了.

Thanks in advance. I really need help with this . Had been trying for so many days.

示例

'm1.labs.terad  ata.com'
'us er5'
'user)5'
'def\ault'

找到了4个令牌.请注意，字符串周围的单引号应存在.预先感谢您的帮助.

There were 4 tokens found. Please note that the single quote around the string should be there. Thanks in advance for help.

但是现在如果我的字符串是

But now if my string is

 s = "server ('m1.labs.terad  ata.com') username ('us ''er5') password('user)5') dbname ('def\\ault')";

输出应为:

   'm1.labs.terad  ata.com'
    'us 'er5'   <<<<<<<<<<<<<<<<<<<
    'user)5'
    'def\ault'

推荐答案

但是我如何制作正则表达式，以便它能够提取转义的单引号(示例用户名(用户"5")应提取为用户5".

But how can I make the regex so that it is able to extract escaped single quotes (example username (user''5) should be extracted as 'user'5'.

U.那是你的意思?我正确有关X/Y问题.

Ugh. Is that what you meant? I was right about X/Y problem then.

注意:您所描述的被称为转义特殊字符.逃脱特殊字符的两种常见方法:

Note: What you describe is known as escaping special characters. Two common ways to escape special characters:

1. 重复此操作(例如printf("100%%");以打印100%)

2. 使用另一个转义符(通常是反斜杠)来引入它.例如.

1. repeat it (e.g. printf("100%%"); to print 100%)

2. introduce it using another escape (usually backslash). E.g.

std::cout << "Hello \"World\"" << std::endl;

或者，再一个复杂的例子:

Or, one more intricate example:

std::cout << "Newline is \\n" << std::endl;

在这里:只需添加q >> char_(q)即可接受重复的引号作为引号转义:

Here you go: just add q >> char_(q) to accept repeated quotes as quote-escape:

auto quoted = [](char q) { 
    return lexeme[ q >> *(
              q >> char_(q)  // accept repeated quotes as quote-escape
            | '\\' >> char_  // accept backs-slash escape
            | char_ - q      // accept any other non-quote
         ) >> q]; };

相对于 在Coliru上直播

#include <iostream>
#include <boost/spirit/home/x3.hpp>
#include <boost/fusion/adapted/std_pair.hpp>
#include <map>

using Config = std::map<std::string, std::string>;
using Entry  = std::pair<std::string, std::string>;

namespace parser {
    using namespace boost::spirit::x3;

    template <typename T> auto as = [](auto p) { return rule<struct _, T> {} = p; };
    auto quoted = [](char q) { return lexeme[q >> *(q >> char_(q) | '\\' >> char_ | char_ - q) >> q]; };

    auto value  = quoted('\'') | quoted('"');
    auto key    = lexeme[+alpha];
    auto pair   = key >> '(' >> value >> ')';
    auto config = skip(space) [ *as<Entry>(pair) ];
}

Config parse_config(std::string const& cfg) {
    Config parsed;
    auto f = cfg.begin(), l = cfg.end();
    if (!parse(f, l, parser::config, parsed))
        throw std::invalid_argument("Parse failed at " + std::string(f,l));
    return parsed;
}

int main() {
    auto const text = "server ('m1.labs.teradata.com') username ('use'')r_*5') password('u\" er 5') dbname ('default')";
    Config cfg = parse_config(text);

    for (auto& setting : cfg)
        std::cout << "Key " << setting.first << " has value " << setting.second << "\n";
}

打印

Key dbname has value default
Key password has value u" er 5
Key server has value m1.labs.teradata.com
Key username has value use')r_*5

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