Token.h

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/*
 * This file is part of KnowRob, please consult
 * https://github.com/knowrob/knowrob for license details.
 */
 
#ifndef KNOWROB_TOKEN_H
#define KNOWROB_TOKEN_H
 
#include <memory>
#include <map>
#include <vector>
#include <string>
#include "knowrob/Printable.h"
 
namespace knowrob {
    enum class TokenType : uint8_t {
        // A control token is used to control the evaluation pipeline.
        CONTROL_TOKEN = 0,
        // An answer token is the result of a query evaluation.
        ANSWER_TOKEN
    };
 
    class Token : public Printable {
    public:
        explicit Token(TokenType tokenType) : tokenType_(tokenType) {};
 
        virtual ~Token() = default;
 
        TokenType tokenType() const { return tokenType_; }
 
        size_t hash() const;
 
        std::string stringForm() const;
 
        bool isControlToken() const { return tokenType() == TokenType::CONTROL_TOKEN; }
 
        bool isAnswerToken() const { return tokenType() == TokenType::ANSWER_TOKEN; }
 
        bool indicatesEndOfEvaluation() const { return isTerminalToken_; }
 
        // Printable interface
        void write(std::ostream &os) const override { os << stringForm(); }
 
    protected:
        TokenType tokenType_;
        bool isTerminalToken_ = false;
    };
 
    // alias
    using TokenPtr = std::shared_ptr<const Token>;
    using TokenMap = std::map<uint32_t, std::vector<TokenPtr>>;
}
 
#endif //KNOWROB_TOKEN_H