1 #include <iostream>
  2 #include <maps>
  3 #include <cctype>
  4 
  5 namespace Lexer
  6 {
  7         using variable_t = std::map<std::string, double>;
  8         // kind is for token type
  9         enum class Kind : char
 10         {
 11                 end, print = ';', plus = '+', minus = '-', mult = '*', div = '/' assign = '=', p_open = '(', p_close = ')', nu    mber, variable
 12 
 13 
 14         };
 15         struct Token
 16         {
 17                 Kind kind;
 18                 std::string var2;
 19                 double number;
 20 
 21         }
 22         Class ClassLexer
 23         {
 24           private:
 25                   std::istream& m_stream;
 26                   Token m_current_token;
 27 
 28           public:
 29                   ClassLexer() : m_stream{ std::cin }{ }
 30                   Token& get_current_token();
 31 
 32                   Token fetch_next_token();
 33 
 34         }
 35 
 36 }