recursive dereferencing library

[sebastian]

I have a dereferencing template that I believe to be implemented
correctly and complete, but I would like to have it checked for
correctness to be sure. is this the right forum for such a thing?

[jason.cipriani@gmail.com]

Re: recursive dereferencing library

Sure, give it a whirl. At the bare minimum you'll get lots of good
advice about undefined gotchas and other weird stuff. As far actually
checking the syntax (not necessarily correctness of your
implementation) , you can also try compiling your code with Comeau's
online compiler here:

http://www.comeaucomputing.com/tryitout/

Jason

"sebastian" <smgarth2u@yaho o.comwrote in message
news:
62973aa1-2f16-490f-9a71-103387610fee...l egroups.com...

>I have a dereferencing template that I believe to be implemented
correctly and complete, but I would like to have it checked for
correctness to be sure. is this the right forum for such a thing?

[Gianni Mariani]

Re: recursive dereferencing library

sebastian wrote:

I have a dereferencing template that I believe to be implemented
correctly and complete, but I would like to have it checked for
correctness to be sure. is this the right forum for such a thing?

If it's a question about the proper use of C++ then it is appropriate.

[sebastian]

Re: recursive dereferencing library

// extract.hpp

#ifndef XTD_EXTRACT_HPP
#define XTD_EXTRACT_HPP

namespace xtd {

/*
template to be specialized for user defined types
*/

template < typename Type >
struct content
{
typedef Type type;
typedef type & reference;

static inline
reference
extractor( reference object )
{
return object;
}
};

/*
user entry point
*/

template < typename Type >
inline
typename content< Type >::reference
extract( Type & object )
{
return content< Type >::extractor( object );
}

/*
specializations for references and pointers
*/

template < typename Type >
struct content< Type & >
{
typedef typename content< Type >::type type;
typedef type & reference;

static inline
reference
extractor( Type & object )
{
return extract( object );
}
};

template < typename Type >
struct content< Type * >
{
typedef typename content< Type >::type type;
typedef type & reference;

static inline
reference
extractor( Type * object )
{
return extract( *object );
}
};

template < typename Type >
struct content< Type * const >
{
typedef typename content< Type >::type type;
typedef type & reference;

static inline
reference
extractor( Type * const object )
{
return extract( *object );
}
};

/*
generic function object
*/

struct extractor
{
template < typename Type >
inline
typename content< Type >::reference
operator ( ) ( Type & object )
{
return extract( object );
}
};

} // namespace xtd

#endif // XTD_EXTRACT_HPP

// pointer_example .cpp

#include <iostream>
#include "extract.hp p"

using namespace std;
using namespace xtd;

int
main( void )
{
int
i = 1024,
* p = &i,
** pp = &p,
*** ppp = &pp;
extract( ppp )++;
cout << extract( ppp ) << endl;
return 0;
}

// auto_pointer_sp ecialization_ex ample.cpp

#include <iostream>
#include <memory>
#include "extract.hp p"

namespace xtd {

template < typename Type >
struct content< std::auto_ptr< Type
{
typedef typename content< Type >::type type;
typedef type & reference;

static inline
reference
extractor( std::auto_ptr< Type & object )
{
return extract( *object.get( ) );
}
};

template < typename Type >
struct content< std::auto_ptr< Type const >
{
typedef typename content< Type >::type type;
typedef type & reference;

static inline
reference
extractor( std::auto_ptr< Type const & object )
{
return extract( *object.get( ) );
}
};

} // namespace xtd

using namespace std;
using namespace xtd;

int
main( void )
{
auto_ptr< auto_ptr< int
ap( new auto_ptr< int >( new int( 1024 ) ) );
extract( ap )++;
cout << extract( ap ) << endl;
return 0;
}

[Gianni Mariani]

Re: recursive dereferencing library

sebastian wrote:

// extract.hpp

.... what problem are you trying to solve ?

It's very clever but I'm not sure it's really needed.

[sebastian]

Re: recursive dereferencing library

>... what problem are you trying to solve ?

the sole purpose of the library is to simplify complex dereferencing
accesses. also, it often allows the underlying storage of data to
change without necessarily changing the accessor code.

>but I'm not sure it's really needed.

its necessity or usefulness depends on the individual, I suppose.