Re: [boost] interest in properties library

Subject: Re: [boost] interest in properties library
From: Sergey Sadovnikov (flex_ferrum_at_[hidden])
Date: 2008-12-20 18:20:52

Hello, Daniel.

Saturday, December 20, 2008 at 4:29:53 PM you wrote:

DO> What I still want to do is enable simpler syntax and maybe signals
DO> triggered by property and other goodies, but that is actually rather  
DO> simple to do, using bind and/or lambda.

Some time ago I showed another way to define properties for the class.
I think what this way quite simpler. Take a look:

Some class which describes game item:
class Item
{
public:
        Item() : properties__(this) {;} // that is all you need to 		 // initialize properties for the class instance.

        virtual ~Item() {;}

        PROPERTIES(Item,
                // Static information about item
                PROPERTY(SItemInfo const*, ItemInfo)
                // Quantity of the stored items (with default 			  // initializer
                PROPERTY_I(size_t, Quantity, 0)
                // Flag which indicates what item is on the base
                PROPERTY_I(bool, IsOnTheBase, false)
                );
};
Usage of this class in the code:

boost::shared_ptr<Item> i(new Item());

i->Quantity = quantity;

Class 'Item' contains simple properties whose directly mapped to the
data members.

Another class, which contains "getter" property:

class Module
{
public:
        PROPERTIES(Module,
                // Common information about module
                RO_PROPERTY(SModuleInfo, ModuleInfo, GetModuleInfo)
                );

        virtual const SModuleInfo& GetModuleInfo() const {return m_ModuleInfo;}
};

This property can be accessed in the same way:
SModuleInfo mi = module.ModuleInfo;

or in the 'function-style' way:
int size = module.ModuleInfo().ModuleSize;

Also you can define n-arity indexer properties:

class Base : public IBase
{
public:
PROPERTIES(Base,
RO_INDEX_PROPERTY(const IModule*, Map, 2, (TPARAM, TPARAM), GetModule)
);
};

Usage is:
Base& b = ...;
IModule* m = b.Map[1][2];

, virtual properties:

class IModule
{
public:
        PROPERTIES(IModule,
        // definition of the abstract property
        ABSTRACT_RO_PROPERTY(SModuleInfo, ModuleInfo)
        );
};
-- 
class Module : public IModule
{
public:
	PROPERTIES(Module,
	// Implementation of the abstract property
	IMPLEMENT_PROPERTY(IModule, RO_PROPERTY(SModuleInfo, ModuleInfo, GetModuleInfo))
	);
enumerate properties in runtime, simple serialize/deserialize properties and so on.
Best Regards,
 Sergey                          mailto:flex_ferrum_at_[hidden]