grammar.hpp

#pragma once
#include <string>
#include <unordered_map>
#include <vector>
 
using production = std::vector<std::string>;
 
struct Grammar {

    explicit Grammar(std::string filename);

    void ReadFromFile();

    void AddRule(const std::string& antecedent, const std::string& consequent);

    void SetAxiom(const std::string& axiom);

    bool HasEmptyProduction(const std::string& antecedent);

    std::vector<std::pair<const std::string, production>>
    FilterRulesByConsequent(const std::string& arg);

    void Debug();

    static std::vector<std::string> Split(const std::string& s);

    static bool HasLeftRecursion(const std::string&              antecedent,
                                 const std::vector<std::string>& consequent);

    std::unordered_map<std::string, std::vector<production>> g_;

    std::string axiom_;

    const std::string kFilename;
};