:github_url: https://github.com/srbhp/nrgplusplus


.. _program_listing_file_utils_configPerser.hpp:

Program Listing for File configPerser.hpp
=========================================

|exhale_lsh| :ref:`Return to documentation for file <file_utils_configPerser.hpp>` (``utils/configPerser.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #pragma once
   #include <fstream>
   #include <iostream>
   #include <map>
   #include <regex>
   #include <string>
   class configPerser {
     // # start starts with comment
     // spaces are ignored
     // We need to specify the configFileName before
     // we call the constructor
     // configParser::configFileName = "config.txt" ;
     //
     // get the values of a key as
     //
     // std::cout << "key: " << configParser().get<double>("key");
     std::map<std::string, std::string> config;
   
   public:
     const inline static std::string configFileName;
     configPerser() {
       // this function is only called once
       if (configFileName.empty()) {
         throw std::runtime_error("configParser::gfilename is empty");
       }
       std::ifstream file(configFileName);
       if (!file.is_open()) {
         std::cout << configFileName << ":File not found" << std::endl;
         return;
       }
       std::string line;
       while (std::getline(file, line)) {
         if (line.empty() || line[0] == '#') {
           continue;
         }
         // remove empty spaces
         // line = std::regex_replace(line, std::regex("\\s+"), "");
         std::string            key;
         std::string            value;
         std::string::size_type pos = line.find('=');
         if (pos == std::string::npos) {
           continue;
         }
         key = line.substr(0, pos);
         // remove spaces from the beginning and the end of the key
         key   = std::regex_replace(key, std::regex("\\s+"), "");
         value = line.substr(pos + 1);
         // remove spaces from the beginning and the end of the key
         value       = std::regex_replace(value, std::regex("^ +| +$"), "$1");
         config[key] = value;
       }
     }
     template <typename T> T get(const std::string &key) {
       if (config.find(key) == config.end()) {
         throw std::runtime_error(key + ": key not found!" + "from the file " +
                                  configFileName);
       }
       std::cout << "configPerser:  " << key << "  " << config[key] << std::endl;
       // double
       if constexpr (std::is_same_v<T, double>) {
         return std::stod(config[key]);
       }
       // int
       if constexpr (std::is_same_v<T, int>) {
         return std::stoi(config[key]);
       }
       // bool
       if constexpr (std::is_same_v<T, bool>) {
         bool check = false;
         if (config[key] == "true") {
           check = true;
           return true;
         }
         if (config[key] == "false") {
           check = true;
           return false;
         }
         if (!check) {
           throw std::runtime_error(key + ": key not found!" + "from the file " +
                                    configFileName);
         }
       }
       // string
       if constexpr (std::is_same_v<T, std::string>) {
         return config[key];
       }
       // tuple
       //
     }
     void print() {
       for (auto [key, value] : config) {
         std::cout << key << ":\t" << value << std::endl;
       }
     }
   };