Question

I have to write following type of code

if ( itr->second == "char" ) 
{
    MemberProperty<Owner,char> *ptr = (MemberProperty<Owner, char> *)GetterSetterItr->second;
    pw->writeChar(itr->first.c_str() ,(pOwner->*(ptr->m_Getter))());
} else if ( itr->second == "wchar" ) {
   MemberProperty<Owner,wchar_t> *ptr = (MemberProperty<Owner, wchar_t> *)GetterSetterItr->second;
   pw->writeWideChar(itr->first.c_str() ,(pOwner->*(ptr->m_Getter))());
}

There are going to be many types, is there any c++ trick, preferably template tricks, to reduce this to one single call for this type of code.

Answer 1

Assuming writeChar() and writeWideChar() are identical except for parameter types, you could restructure your code like this:

if (it->second == "char")
  pw->writeChar<char>(itr->first, GetterSetterItr->second);
else if (itr->second == "wchar")
  pw->writeChar<wchar_t>(itr->first, GetterSetterItr->second);

Then in the class of which *pw is an instance, replace writeChar and writeWideChar with a template member function:

template <typename CharType>
void writeChar(std::string str, /*the type of GetterSetterItr->second*/ arg) {
  MemberProperty<Owner, CharType> *ptr = (MemberProperty<Owner, CharType>*)arg;
  // the rest of code of old writeChar() and writeWideChar()
}