lexer.h

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#pragma once
 
#include <cstdint>
#include <fstream>
#include <ostream>
#include <string>
#include <utility>
#include <vector>
#include <expected>
 
#include "error.h"
 
namespace picceler {

struct Token {
  enum class Type : size_t { IDENTIFIER, NUMBER, STRING, SYMBOL, EOF_TOKEN, UNKNOWN };

  std::string typeToString() const;

  std::string toString() const {
    return std::format("Token(type: {}, value: '{}', line: {}, column: {})", typeToString(), _value, _line, _column);
  }
 
  Type _type;
  std::string _value;
  size_t _line;
  size_t _column;
};

class Lexer {
public:
  Lexer();

  Result<void> setSource(const std::string &source);

  Result<Token> nextToken();

  Result<Token> peekToken();

  void skipWhitespace();

  Result<std::vector<Token>> tokenizeAll();
 
private:
  bool eof() const;

  char peek() const;

  char get();

 
  bool isIdentifier(char ch) const;
  bool isSymbol(char ch) const;

  Result<Token> readIdentifier(std::pair<size_t, size_t> start);

  Result<Token> readNumber(std::pair<size_t, size_t> start);

  Result<Token> readString(std::pair<size_t, size_t> start);

  Result<Token> readSymbol(std::pair<size_t, size_t> start);
 
private:
  std::ifstream _file;
  std::string _buffer;
  size_t _position;
  size_t _line;
  size_t _column;
};

std::ostream &operator<<(std::ostream &os, const Token &token);
 
} // namespace picceler