我有以下代码:
int main()
{
string s = "server ('m1.labs.teradata.com') username ('use\\')r_*5') password('u\" er 5') dbname ('default')";
regex re("(\'[!-~]+\')");
sregex_token_iterator i(s.begin(), s.end(), re, 1);
sregex_token_iterator j;
unsigned count = 0;
while(i != j)
{
cout << "the token is "<<*i<< endl;
count++;
}
cout << "There were " << count << " tokens found." << endl;
return 0;
}
使用上面的正则表达式,我想在paranthesis和单引号之间提取字符串:out out应该是这样的:
the token is 'm1.labs.teradata.com'
the token is 'use\')r_*5'
the token is 'u" er 5'
the token is 'default'
There were 4 tokens found.
基本上,正则表达式应该在&#34;之间提取所有内容。 (&#39;&#34;和&#34;&#39;)&#34;。它可以是任何空间,特殊字符,引用或结束的parathesis。 我之前使用过以下正则表达式:
boost::regex re_arg_values("(\'[!-~]+\')");
但是不接受空间。请有人帮我解决这个问题。提前谢谢。
答案 0 :(得分:2)
以下是使用Spirit X3创建语法以实际解析此问题的示例。我想解析(key-&gt; value)对的映射,这比盲目假设名称总是相同更有意义:
using Config = std::map<std::string, std::string>;
using Entry = std::pair<std::string, std::string>;
现在,我们使用X3设置一些语法规则:
namespace parser {
using namespace boost::spirit::x3;
auto value = quoted("'") | quoted('"');
auto key = lexeme[+alpha];
auto pair = key >> '(' >> value >> ')';
auto config = skip(space) [ *as<Entry>(pair) ];
}
助手as<>
和quoted
是简单的lambdas:
template <typename T> auto as = [](auto p) { return rule<struct _, T> {} = p; };
auto quoted = [](auto q) { return lexeme[q >> *('\\' >> char_ | char_ - q) >> q]; };
现在我们可以直接将字符串解析为地图:
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;
}
演示程序
int main() {
Config cfg = parse_config("server ('m1.labs.teradata.com') username ('use\\')r_*5') password('u\" er 5') dbname ('default')");
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
<强> Live On Coliru 强>
#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 = [](auto q) { return lexeme[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() {
Config cfg = parse_config("server ('m1.labs.teradata.com') username ('use\\')r_*5') password('u\" er 5') dbname ('default')");
for (auto& setting : cfg)
std::cout << "Key " << setting.first << " has value " << setting.second << "\n";
}
如果您想学习如何提取原始输入:只需尝试
auto source = skip(space) [ *raw [ pair ] ];
如下:
using RawSettings = std::vector<std::string>;
RawSettings parse_raw_config(std::string const& cfg) {
RawSettings parsed;
auto f = cfg.begin(), l = cfg.end();
if (!parse(f, l, parser::source, parsed))
throw std::invalid_argument("Parse failed at " + std::string(f,l));
return parsed;
}
int main() {
for (auto& setting : parse_raw_config(text))
std::cout << "Raw: " << setting << "\n";
}
打印: Live On Coliru
Raw: server ('m1.labs.teradata.com')
Raw: username ('use\')r_*5')
Raw: password('u" er 5')
Raw: dbname ('default')
答案 1 :(得分:0)
修复一些语法和样式问题:
\
"
,语法错误#include <boost/regex.hpp>
#include <boost/range/iterator_range.hpp>
#include <iostream>
int main() {
std::string s = "server ('m1.labs.teradata.com') username ('use\')r_*5') password('u' er 5') dbname ('default')";
boost::regex re(R"(('([^'\\]*(?:\\[\s\S][^'\\]*)*)'))");
size_t count = 0;
for (auto tok : boost::make_iterator_range(boost::sregex_token_iterator(s.begin(), s.end(), re, 1), {})) {
std::cout << "Token " << ++count << " is " << tok << "\n";
}
}
打印
Token 1 is 'm1.labs.teradata.com'
Token 2 is 'use'
Token 3 is ') password('
Token 4 is ' er 5'
Token 5 is 'default'