Re: how to implement a simple class forname?

From:

"Victor Bazarov" <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Wed, 19 Jul 2006 15:23:33 -0400

Message-ID:

<e9m0rp$6ud$1@news.datemas.de>

Manuel wrote:

Thomas J. Gritzan wrote:

Manuel schrieb:

Victor Bazarov wrote:

Manuel wrote:

Victor Bazarov wrote:

Manuel wrote:

I need implement a map of member functions of some class.
This map is formed by a string and a pointer to the member
function.

Member of what class? What arguments does it take? What type
does it return?

The members are of different class that derive of a superclass and
this members do
not return anything.

What's the point to have member functions of different classes
stored in the same container? What's _common_ about those
functions? How do you intend to use those map elements?

And if they don't return anything, the return value type is 'void'.

V
--
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The methods are used to get objects. This methods have the same name
and the same parameters. it is like a constructor.
I have got a xml file that specifies the objects that i want with
his state

So the methods are static functions?
That's an information we need to help you. Give an example of such a
class/function (a minimal example).

You can typedef your function type and put pointers to that in the
map:

typedef void factory_t(baseclass&, const parameters&);

std::map< std::string, factory_t* > your_map;

--
Thomas

well Thomas, you give me an idea to solve the problem.

i can create a static method in the factory class for each one of the
classes and then in the map it save the pointer to this methods.

So, when I need a object i call to factory::(*pointer)(const
paramaters&)

something as well as this:

typedef float (*MyFuncPtrType)(const paramaters&);

map<std::string, MyFuncPtrType>;

map["method1"] = &method1;
map["method2"] = &method2;

when i need a object i call: factory::(*map["method1"])(parameters).

I think that this can work. what do you think?

If I may... This sounds OK, only to take address of a member function
you need the class before the name:

     map["method1"] = &OneClass::method1;
     map["method2"] = &TwoClass::method2;

And when you call it, you can't prepend it with 'factory::'. You just
use

     map["method1"](parameters);

V
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