text: #pragma once
  #include <string>
  #include <vector>
  
  namespace util {
  
  bool                     has_prefix(std::string a, std::string b);
  std::string              to_lower(std::string st);
  std::vector<std::string> split(std::string st, std::string token);
  std::string join(std::vector<std::string> st, std::string separator); // TODO templatize
  
  };
  