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Wave: a Standard conformant C++ preprocessor library

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10 Jan 200413 min read 392.1K   4.4K   81  
Describes a free and fully Standard conformant C++ preprocessor library
/*=============================================================================
    Wave: A Standard compliant C++ preprocessor

    Definition of the position_iterator and file_position templates
    
    Copyright (c) 2001-2004 Hartmut Kaiser
    http://spirit.sourceforge.net/

    Use, modification and distribution is subject to the Boost Software
    License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
    http://www.boost.org/LICENSE_1_0.txt)

    See Copyright.txt for full acknowledgements.
=============================================================================*/

#if !defined(FILE_POSITION_H_52BDEDF7_DAD3_4F24_802F_E66BB8098F68_INCLUDED)
#define FILE_POSITION_H_52BDEDF7_DAD3_4F24_802F_E66BB8098F68_INCLUDED

#include <string>
#include <ostream>

#include <boost/spirit/iterator/position_iterator.hpp>

///////////////////////////////////////////////////////////////////////////////
namespace wave {
namespace util {

///////////////////////////////////////////////////////////////////////////////
//
//  file_position
//
//  A structure to hold positional information. This includes the filename,
//  line number and column number of a current token position.
//
///////////////////////////////////////////////////////////////////////////////

template <typename StringT = std::string>
struct file_position {

public:
    typedef StringT string_t;
    
    file_position()
    :   file(), line(1), column(1)
    {}
    explicit file_position(string_t const& file_, int line_ = 1, 
            int column_ = 1)
    :   file(file_), line(line_), column(column_)
    {}

// accessors
    string_t const &get_file() const { return file; }
    int get_line() const { return line; }
    int get_column() const { return column; }
    
    void set_file(string_t const &file_) { file = file_; }
    void set_line(int line_) { line = line_; }
    void set_column(int column_) { column = column_; }
    
private:
    string_t file;
    int line;
    int column;
};

template <typename StringT>
bool operator== (file_position<StringT> const &lhs, 
    file_position<StringT> const &rhs)
{
    return lhs.get_column() == rhs.get_column() && 
        lhs.get_line() == rhs.get_line() && lhs.get_file() == rhs.get_file();
}

template <typename StringT>
inline std::ostream &
operator<< (std::ostream &o, file_position<StringT> const &pos)
{
    o << pos.get_file() << "(" << pos.get_line() << ")";
    return o;
}

#if !defined(WAVE_STRINGTYPE)
#define WAVE_STRINGTYPE std::string
#endif // !defined(WAVE_STRINGTYPE)

typedef file_position<WAVE_STRINGTYPE> file_position_t;

///////////////////////////////////////////////////////////////////////////////
//
//  position_iterator
//
//  The position_iterator used by Wave is now based on the corresponding Spirit 
//  type. This type is used with our own file_position though. The needed
//  specialization of the boost::spirit::position_policy class is provided 
//  below.
//
///////////////////////////////////////////////////////////////////////////////

template <typename IteratorT, typename PositionT>
struct position_iterator 
:   boost::spirit::position_iterator<IteratorT, PositionT>
{
    typedef boost::spirit::position_iterator<IteratorT, PositionT> base_t;
    
    position_iterator()
    {
    }
    
    position_iterator(IteratorT const &begin, IteratorT const &end,
            PositionT const &pos)
    :   base_t(begin, end, pos)
    {
    }
};

///////////////////////////////////////////////////////////////////////////////
}   // namespace util
}   // namespace wave

///////////////////////////////////////////////////////////////////////////////
namespace boost { 
namespace spirit { 

///////////////////////////////////////////////////////////////////////////////
//
//  The boost::spirit::position_policy has to be specialized for our 
//  file_position class
//
///////////////////////////////////////////////////////////////////////////////

    template <>
    class position_policy<wave::util::file_position_t> {

    public:
        position_policy()
            : m_CharsPerTab(4)
        {}

        void next_line(wave::util::file_position_t &pos)
        {
            pos.set_line(pos.get_line() + 1);
            pos.set_column(1);
        }

        void set_tab_chars(unsigned int chars)
        {
            m_CharsPerTab = chars;
        }

        void next_char(wave::util::file_position_t &pos)
        {
            pos.set_column(pos.get_column() + 1);
        }

        void tabulation(wave::util::file_position_t &pos)   
        {
            pos.set_column(pos.get_column() + m_CharsPerTab - 
                (pos.get_column() - 1) % m_CharsPerTab);
        }

    private:
        unsigned int m_CharsPerTab;
    };

///////////////////////////////////////////////////////////////////////////////
}   // namespace spirit 
}   // namespace boost 

#endif // !defined(FILE_POSITION_H_52BDEDF7_DAD3_4F24_802F_E66BB8098F68_INCLUDED)

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United States United States
Actively involved in Boost and the development of the Spirit parser construction framework.

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