/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.

Author: Leonardo de Moura
*/
#pragma once
#include <iostream>
#include <vector>
#include "mpq.h"
#include "name.h"

namespace lean {
/**
    \brief Lean scanner.
*/
class scanner {
public:
    enum class token {
        LeftParen, RightParen, LeftCurlyBracket, RightCurlyBracket, Colon, Comma, Period, Lambda, Pi, Arrow,
        Id, CommandId, Int, Decimal, Eq, Assign, Eof
    };
protected:
    int                m_spos; // position in the current line of the stream
    char               m_curr;  // current char;

    int                m_line;  // line
    int                m_pos;   // start position of the token
    std::istream &     m_stream;

    mpq                m_num_val;
    name               m_name_val;
    std::string        m_buffer;

    char curr() const { return m_curr; }
    void new_line() { m_line++; m_spos = 0; }
    void next();
    bool check_next(char c);
    void  read_comment();
    token read_a_symbol();
    token read_b_symbol();
    token read_c_symbol();
    token read_number();
    bool is_command(name const & n) const;

public:
    scanner(std::istream& stream);
    ~scanner();

    int get_line() const { return m_line; }
    int get_pos() const { return m_pos; }
    token scan();

    name const & get_name_val() const { return m_name_val; }
    mpq const & get_num_val() const { return m_num_val; }
};
std::ostream & operator<<(std::ostream & out, scanner::token const & t);
}