Yes, you can define your types based on const char* and overload template functions on them. //using structs to skip explicit public access specifiers ///header extern const char SomeName[]; template<const char*> struct TypeId {}; typedef TypeId<SomeName> MemberX_Accessor; struct ClassWithMembers { void access(MemberX_Accessor) { ... } template<class T> void access(T) { /// issue error here, no accessor specified!!! } private: MemberX x; }; ///cpp extern const char SomeName[] ="memberX"; I hope that example brings you to some useful ideas. Regards, Ovanes On Jan 29, 2008 3:34 PM, Joseph Fradley <joe.fradley@fradeng.com> wrote:
I have a problem that I would like to solve in the most generic non-intrusive way possible (such as boost serialization). What I want is to access class members both via it's initially designed accessors but also via a "const char *" key. In addition, I want to pass list of key's (via a vector of const char * or a single delimited multikey char *) to get nested member access.
For example: ... // these should be equivalent Point p; int val; val = p.x; val = p.getX(); p.getMemberValue("x", val);
// there also Rectangle r; int val; Point pVal; r.getMemberValue("corner:x", val); r.getMemberValue("corner", pVal);
I thought about having a templated function similar to the serialize() function called 'getMemberValue()', where each 'if' block below could be wrapped into a MACRO taking just the member name.
template< class T > bool getMemberValue(const char *key, T & value) { if(!strcmp(key, "member")) { value = this->member; return true; } return false; }
This appears to work fine for one level deep but if I want the behavior such as the above rectangle example, I run into trouble. I end up with a function implementation like this for the 'Rectangle' class
template< Point > bool getMemberValue(const char *key, Point & value) { if(!strcmp(key, "corner")) { value = this->corner; // Point return true; } if(!strcmp(key, "width")) { value = this->width; // int return true; } if(!strcmp(key, "height")) { value = this->height; // int return true; } return false; }
This fails because it ends up trying to set an integer value to a Point variable.
Anybody have any suggestions?
Joe
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