I want to know whether the object that would be created from a class reference is an instance of a particular class or any of its descendants.
In other words, I want a Boolean expression such as
var is TMyClass
but where var is replaced with an expression involving a class reference variable. It sounds easy but has me completely stumped.
I could create an instance var := classRefVar.Create, test it, and then destroy it, but that's a huge overhead.
Oddly, the compiler won't let me have
classRefVar(nil) is TMyClass
but is happy with the seemingly equivalent syntactically, but useless
TMyClass(nil) is TMyClass
Obviously, the expression
classRefVar = TMyClass
is no good because the classRefVar might refer to a descendent of TMyClass.
I'm expecting to kick myself when I see the answer...
