/*
 * TokenStream.h
 *
 *  Created on: Feb 8, 2010
 *      Author: petergoodman
 *     Version: $Id$
 */

#ifndef TOKENGENERATOR_H_
#define TOKENGENERATOR_H_

#include <istream>
#include <sstream>
#include <string>
#include <cstring>

#include <assert.h>

#include "Token.h"
#include "ParseError.h"

using namespace std;

struct TokenGenerator {

    struct iterator : std::iterator<input_iterator_tag, Token *> {

        explicit iterator(string::iterator begin,
                          string::iterator end) throw(ParseError);
        ~iterator();

        // iterator interface
        reference operator*();
        iterator &operator++ ();
        iterator operator++ (int);
        bool operator!=(const iterator& other);
        bool operator==(const iterator& other);

    private:

        // make things happen
        string::iterator it;
        string::iterator it_end;
        bool at_end;

        Token *curr;
        bool generateNext() throw(ParseError);
        Token *parseIntLiteral();
        Token *parseStringLiteral();
        Token *parseAlphaNumName(const Token::Type type);
        Token *parseOperator();
    };

    // operations

    TokenGenerator(const string &s = "");
    ~TokenGenerator();

    void assign(const string &s);

    // iterators
    iterator begin() throw(ParseError);
    iterator end() throw(ParseError);

private:
    static const string operators;
    string str;
};

#endif /* TOKENGENERATOR_H_ */