#ifndef __SCANNER_H
#define __SCANNER_H
/*
5D programming language
Copyright (C) 2011  Danny Milosavljevic
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
/* C++ has a template isxdigit which conflicts with the macro isxdigit */
#undef isxdigit
#include <assert.h>
#include <sstream>
#include <string>
#include <list>
#include "AST/Symbol"
#include "AST/AST"

namespace Scanners {

class ParseException : std::exception {
	char* message;
public:
	ParseException(const char* s) throw();
	virtual const char* what() const throw();
};

#define SCROLL_LEFT(x, n) \
	x[0] = x[1]; \
	x[1] = x[2]; \
	x[2] = x[3]; \
	x[3] = n;
#define SCROLL_RIGHT(x) \
	(x[4] = x[3], x[3] = x[2], x[2] = x[1], x[1] = x[0], x[4])

class Scanner : public AST::Node {
protected:
	FILE* input_file;
	//std::stringstream matchtext;
	int position;
	int previous_position;
	int line_number;
	int column_number;
	char* input_name;
	int backtracking_column_numbers[5]; /* last is dummy */
	bool backtracking_beginning_of_line[5]; /* last is dummy */
	bool B_honor_indentation;
	bool B_beginning_of_line;
	int brace_level; // non-indentation braces.
	void update_indentation();
	inline int increment_position(int input) {
		++position;
		if(input == '\n') {
			SCROLL_LEFT(backtracking_column_numbers, column_number)
			SCROLL_LEFT(backtracking_beginning_of_line, B_beginning_of_line)
			++line_number;
			column_number = 0;
			B_beginning_of_line = true;
		} else if(B_beginning_of_line && (input != ' ' && input != '\t' && input != EOF && input != '\r')) {
			B_beginning_of_line = false;
			update_indentation();
			++column_number;
		} else
			++column_number;
		return(input);
	}
	inline int decrement_position(int input) {
		--position;
		assert(input != ' ' && input != '\t');
		if(input == '\n') {
			column_number = SCROLL_RIGHT(backtracking_column_numbers);
			B_beginning_of_line = SCROLL_RIGHT(backtracking_beginning_of_line);
			--line_number;
		} else
			--column_number;
		return(input);
	}
	void increase_brace_level() {
		++brace_level;
	}
	void decrease_brace_level() {
		--brace_level;
	}
	void inject(AST::NodeT input_value);
public:
	AST::NodeT input_value; // read-only
	void push(FILE* input_file, int line_number, const char* input_name);
	void pop(void);
	int get_position(void) const {
		return(previous_position);
	}
	int get_column_number(void) const {
		return(column_number);
	}
	int get_line_number(void) const {
		return(line_number);
	}
	void raise_error(const std::string& expected_text, int got_text);
	void raise_error(const std::string& expected_text, std::string got_text);
	Scanner(void);
	bool EOFP(void) const;
	void ensure_end(void);
	AST::NodeT consume(AST::NodeT expected_value = NULL);
	bool setHonorIndentation(bool value) {
		bool result = B_honor_indentation;
		B_honor_indentation = value;
		return(result);
	}
	virtual std::string toString(void) const;
private:
	std::list<AST::NodeT> injected_input_values;
	bool deinject();
	void parse_token(void);
	void parse_optional_whitespace(void);
	void parse_number(int input);
	void parse_structural(int input);
	void parse_string(int input);
	void parse_special_coding(int input);
	void parse_number_with_base(int input, int base);
	void parse_operator(int input);
	void parse_symbol(int input, int special_prefix = 0, int special_prefix_2 = 0);
};
bool symbol_char_P(int input);

}; /* end namespace Scanners */
#endif /* ndef __SCANNER_H */