Re: [Boost-users] Vector of Polymorphic Pointers

From: Juan Quiroz (juancq_at_[hidden])
Date: 2006-05-01 17:49:26

I forgot to include more details on the ASTNode class, it's actually like
this:

class ASTNode
{
    public:
        ASTNode(string _type="", string _name="", string _value="", string
_type_specifier="");
        virtual ~ASTNode();

        virtual void Code_Gen();
        virtual void DumpOut(FILE *);
...
       void setName(string _name);
        void clear();

    protected:
        string name;
        string type;
        string type_specifier;
        string value;
        // Children nodes
        vector<ASTNode *> children;

    private:

        // Code for serialization
        friend class boost::serialization::access;
        template<class Archive>
        void serialize(Archive & ar, unsigned int version)
        {
            ar & name;
            ar & type;
            ar & type_specifier;
            ar & value;
            ar & children;
        }
};

The derived classes implement the CodeGen and DumpOut methods.
Thank you for your prompt reply!

On 5/1/06, Robert Ramey <ramey_at_[hidden]> wrote:
>
> Hmmm - it looks like ASTNode might not be polymorphic - it doesn't seem
> tohave a virtual function defined.
>
> Try the following change:
> "Juan Quiroz" <juancq_at_[hidden]> wrote in message
> news:f4e027970605011410p207777c1m1abef4f5771acc07_at_mail.gmail.com...
>
> I am trying to serialize a vector of polymorphic pointers.  My code looks
> as
> follows:
>
> class ASTNode{
> ...
> protected:
> vector <ASTNode*> children;
> string name;
> string type;
>
> private:
>    // Code for serialization
>         friend class boost::serialization::access;
>         template<class Archive>
>         void serialize(Archive & ar, unsigned int version)
>         {
>             ar & name;
>             ar & type;
>             ar & children;
>         }
>         virtual ~ASTNode(); // <== try adding this in!
> }
> class ASTNode2: public ASTNode{
> ...
> private:
>   // Code for serialization
>         friend class boost::serialization::access;
>         template<class Archive>
>             void serialize(Archive & ar, unsigned int version)
>             {
>                 // serialize base class information
>                 ar & boost::serialization::base_object<ASTNode>(*this);
>             }
>         // End code for serialization
> }
>
> I use the vector "children" to hold pointers to both base and derived
> objects.  I have tried registering the derived classes at the top of the
> serialize function call, with the use of
> ar.register(static_cast<ASTNode*>(NULL)).  I have also tried using the
> BOOST_CLASS_EXPORT_GUID macro to register the classes in main.  Yet, I
> still
> get a unregistered class exception.  Any guidance would be greatly
> appreciated.
>
>
>
>
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