symbol_table.hpp

#pragma once
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
 
enum symbol_type { NO_TERMINAL, TERMINAL, META };
 
struct symbol_table {
    using TokenID = unsigned long;
 
    inline static TokenID INVALID_TOKEN{0};
    inline static TokenID EOF_ID{1};
    inline static TokenID EPSILON_ID{2};
 
    inline static TokenID next_id_{3};

    inline static std::string EOF_{"<<EOF>>"};

    inline static std::string EPSILON_{"<<EPSILON>>"};

    inline static std::vector<std::pair<symbol_type, std::string>> st_{
        {META, ""},     // 0 - INVALID
        {TERMINAL, ""}, // 1 - <<EOF>>
        {META, ""},     // 2 - <<EPSILON>>
    };

    inline static std::unordered_map<std::string, TokenID> lookup_{
        {EOF_, EOF_ID}, {EPSILON_, EPSILON_ID}};

    inline static std::vector<std::string> names_{"", EOF_, EPSILON_};

    inline static std::vector<TokenID> order_{EOF_ID};

    static void PutSymbol(const std::string& identifier,
                          const std::string& regex);

    static void PutSymbol(const std::string& identifier);

    static bool In(TokenID id);
 
    static bool In(const std::string& identifier);

    static bool IsTerminal(TokenID id);

    static std::string GetValue(TokenID id);

    static const std::string& ToString(TokenID id);

    static TokenID ToID(const std::string& identifier);

    static void Debug();
};