variant to prototype...

[werasm]

Hi all,

Traditionally the prototype pattern (cloning) causes
the "cloned" to be copied. Is there an idiom where
the method performing the creation creates the
default type (without cloning). Small example:

template <class T>
struct clonable
{
virtual T* clone() const; //calls new T( *this );
};

template <class T>
struct xxx_able
{
virtual T* xxx() const; //calls new T();
};

Note that this is similar to factory functions, but not
entirely the same as factory functions are aware of
type.

Therefore - I want a prototype that provides the correct
type without cloning. What is the idiom called?

Regards,

Werner

 

[Victor Bazarov]

Traditionally the prototype pattern (cloning) causes
the "cloned" to be copied. Is there an idiom where
the method performing the creation creates the
default type (without cloning). Small example:

template <class T>
struct clonable
{
virtual T* clone() const; //calls new T( *this );
};

template <class T>
struct xxx_able
{
virtual T* xxx() const; //calls new T();
};

Note that this is similar to factory functions, but not
entirely the same as factory functions are aware of
type.

I think you should be able to see a "virtual factory method"
or something like that in the literature.

Therefore - I want a prototype that provides the correct
type without cloning. What is the idiom called?

The "factory method", IIRC.

V