#ifndef LEXER_H
#define LEXER_H

#include <string>
#include <stdexcept>
#include <cstddef>

class SyntaxError : public std::runtime_error {
public:
    int row;
    int col;

    SyntaxError(const std::string& msg, int row_, int col_)
        : std::runtime_error(msg), row(row_), col(col_) {}
};


class Lexer {
public:
    int row;
    int col;

    explicit Lexer(std::string input);

    Lexer& mark();

    std::string extract(int ofs);
    std::string extract();

    char peek(int ahead) const;
    char peek() const;

    char advance();

    bool advanceIf(char ch);
    void advance(char ch);  


    bool skipWhitespace();

    std::string readTo(char delimiter);

    std::string readAlphanumeric();

    std::string readDigits(int radix);

private:
    std::string input_;
    std::size_t pos_;
    std::size_t start_;

    static int digitValue(char c, int radix);
};

#endif // LEXER_H