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// Property lists.
#ifndef _CL_PROPLIST_H
#define _CL_PROPLIST_H
#include "cln/symbol.h"
#include "cln/malloc.h"
namespace cln {
// The only extensible way to extend objects at runtime in an extensible
// and decentralized way (without having to modify the object's class)
// is to add a property table to every object.
// For the moment, only very few properties are planned, so lists should be
// enough. Since properties represent additional information about the object,
// there is no need for removing properties, so singly linked lists will be
// enough.
// This is the base class for all properties.
struct cl_property {
private:
cl_property* next;
public:
cl_symbol key;
// Constructor.
cl_property (const cl_symbol& k) : next (NULL), key (k) {}
// Destructor.
virtual ~cl_property () {}
// Allocation and deallocation.
void* operator new (size_t size) { return malloc_hook(size); }
void operator delete (void* ptr) { free_hook(ptr); }
private:
virtual void dummy ();
// Friend declarations. They are for the compiler. Just ignore them.
friend class cl_property_list;
};
#define SUBCLASS_cl_property() \
void* operator new (size_t size) { return malloc_hook(size); } \
void operator delete (void* ptr) { free_hook(ptr); }
struct cl_property_list {
private:
cl_property* list;
public:
cl_property* get_property (const cl_symbol& key);
void add_property (cl_property* new_property);
// Constructor.
cl_property_list () : list (NULL) {}
// Destructor.
~cl_property_list ();
};
} // namespace cln
#endif /* _CL_PROPLIST_H */