c++ - 使用 std::regex_search 在同一行解析多个宏

Question

我想在同一行中解析宏。所以我在 map 中定义宏:

map<string, string> collection;
collection["ComputerName"] = "Train-Alpha";
collection["State"] = "Unloaded";

宏符号是 $(MacroName) 所以输入行看起来像:

string line = "Running on $(ComputerName) while $(State)";

我使用这个正则表达式:

regex expression("\\$\\(([^}]+)\\)");

但是我下面的代码考虑的是“最大”的子模式而不是最小的:

#include <iostream>
#include <regex>
#include <map>
#include <boost/algorithm/string.hpp>

using namespace std;

void main()
{
    string line = "Running on $(StationName) while $(State)";
    map<string, string> collection;
    collection["Station"] = "Train-Alpha";
    collection["State"] = "unloaded";
    regex pattern("\\($\\([^}]+\\))");
    smatch match;

    while (regex_search(line, match, pattern))
    {
        auto variableName = match[1].str();
        auto it = collection.find(variableName);
        if (it != end(collection))
        {
            auto keyword = "$(" + variableName + ")";
            auto value = it->second;
            boost::replace_all(line, keyword, value);
        }
        else
        {
            break;
        }
    }
    cout << line << endl;
}

Answer 1

您的代码中有一些错误:

1. 应该更改第一个映射值:

   collection["Station"] = "Train-Alpha";
   

   通过

   collection["StationName"] = "Train-Alpha";
   

2. 正则表达式也应该改变:

   regex pattern("\\($\\([^}]+\\))");
   

   通过

   regex pattern("\\$\\(([^)]+)\\)");
   

   或者您也可以使用 Raw string literal避免转义反斜杠(或任何字符):

   regex pattern(R"(\$\(([^)]+)\))");
   

---

See a slightly modified working version on Ideone.