c++ - boost::regex 与 UTF-8 不区分大小写匹配（例如，大写与小写变音符号）

Question

在使用支持 Unicode (ICU) 的国际组件构建 boost::regex 版本 1.52 库后，具有不区分大小写匹配的正则表达式似乎无法按预期处理大写和小写的德语变音符号字符。

static const std::string pattern("^.*" "\303\226" ".*$");
static const std::string   test1("SCH" "\303\226" "NE");
static const std::string   test2("sch" "\303\266" "ne");
static const boost::regex exp(pattern, boost::regex::icase);
const char *result = (boost::regex_match(test1, exp)) ? "Match" : "NoMatch";
std::cout << "Testing \"" << test1 << "\" against pattern \"" << pattern 
    << "\" : " << result << std::endl;
result = (boost::regex_match(test2, exp)) ? "Match" : "NoMatch";
std::cout << "Testing \"" << test2 << "\" against pattern \"" << pattern 
    << "\" : " << result << std::endl;

产量：

Testing "SCHÖNE" against pattern "^.*Ö.*$" : Match
Testing "schöne" against pattern "^.*Ö.*$" : NoMatch

Answer 1

使用 Unicode 和 ICU 字符串类型。

LWS 上的示例。

#include <iostream>
#include <boost/regex.hpp>
#include <boost/regex/icu.hpp>
int main()
{
   static const std::string pattern("^.*" "\303\226" ".*$");
   static const std::string   test1("SCH" "\303\226" "NE");
   static const std::string   test2("sch" "\303\266" "ne");
   static const boost::u32regex exp=boost::make_u32regex(pattern, boost::regex::icase);
   const char *result = (boost::u32regex_match(test1, exp)) ? "Match" : "NoMatch";
   std::cout << "Testing \"" << test1 << "\" against pattern \"" << pattern 
      << "\" : " << result << std::endl;
   result = (boost::u32regex_match(test2, exp)) ? "Match" : "NoMatch";
   std::cout << "Testing \"" << test2 << "\" against pattern \"" << pattern 
      << "\" : " << result << std::endl;
}