On Saturday, October 12, 2013 09:32:09 luminousone wrote: > And again, the casting solution is a bloody hack, it is loaded > with corner cases that will break things if you are not aware of > them. It also requires an allocated instance of that object
Of course, it requires an instance of the object. The point is to test whether an instance is of a type derived from a particular type, not whether a particular type is derived from a particular type. If the OP wants to test whether a particular type is derived from another type, then casting is not the right solution. The way to do that is to use an is expression, e.g. is(Derived : Base). If you really care that the type is a derived type and want to avoid any other type of implicit conversions, then you need to use some compile time reflection to do that, but that's often overkill and completely kills the ability to create class which "inherits" via alias this, which is the main purpose for alias this existing in the first place. > It is bad practice. It's standard practice. Both the online docs and TDPL will tell you to use a cast to determine whether a particular object's type is derived from a particular type. And I completely disagree that it's bad practice, but clearly we're not going to agree on that. - Jonathan M Davis
