src/lexer.h

/*
	Copyright (c) 2014, Santeri Piippo
	All rights reserved.

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions are met:

		* Redistributions of source code must retain the above copyright
		  notice, this list of conditions and the following disclaimer.

		* Redistributions in binary form must reproduce the above copyright
		  notice, this list of conditions and the following disclaimer in the
		  documentation and/or other materials provided with the distribution.

		* Neither the name of the <organization> nor the
		  names of its contributors may be used to endorse or promote products
		  derived from this software without specific prior written permission.

	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
	ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
	WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
	DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
	(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#ifndef BOTC_LEXER_H
#define BOTC_LEXER_H

#include "main.h"
#include "lexer_scanner.h"

class lexer
{
types:
	struct token
	{
		e_token		type;
		string		text;
		string		file;
		int			line;
		int			column;
	};

	using token_list	= list<token>;
	using iterator		= token_list::iterator;

public:
	lexer();
	~lexer();

	void	process_file (string file_name);
	bool	get_next (e_token req = tk_any);
	void	must_get_next (e_token tok = tk_any);
	void	must_get_any_of (const list<e_token>& toks);
	int		get_one_symbol (const string_list& syms);
	void	must_be (e_token tok);
	bool	peek_next (token* tk = null);

	inline bool has_valid_token() const
	{
		return (m_token_position < m_tokens.end() && m_token_position >= m_tokens.begin());
	}

	inline token* get_token() const
	{
		assert (has_valid_token() == true);
		return &(*m_token_position);
	}

	inline bool is_at_end() const
	{
		return m_token_position == m_tokens.end();
	}

	inline e_token get_token_type() const
	{
		return get_token()->type;
	}

	// If @tok is given, describes the token. If not, describes @tok_type.
	static inline string describe_token_type (e_token tok_type)
	{
		return describe_token_private (tok_type, null);
	}

	static inline string describe_token (token* tok)
	{
		return describe_token_private (tok->type, tok);
	}

	static lexer* get_main_lexer();

	inline void skip (int a = 1)
	{
		m_token_position += a;
	}

	string peek_next_string (int a = 1);

private:
	token_list		m_tokens;
	iterator		m_token_position;

	// read a mandatory token from scanner
	void must_get_next_from_scanner (lexer_scanner& sc, e_token tt = tk_any);
	void check_file_header (lexer_scanner& sc);

	static string describe_token_private (e_token tok_type, token* tok);
};

#endif // BOTC_LEXER_H