Hi,
I've got a scene graph which contains multiple inheriting types.
As such, I've been tagging them with a type enum for whenever I
need to do things such as loading a structure from binary.
Up until now I've been using an enum that looks like this:
-------------------------------------------------------------------------------
enum NodeType : uint {
None,
Root,
Sprite,
Camera
}
-------------------------------------------------------------------------------
I'm trying to implement a dynamic type ID assignment system that
utilizes D generics to generate an incremental, unique identifier
for each node without needing to continuously update a master
list. This is what I have so far:
-------------------------------------------------------------------------------
alias NodeTypeID = uint;
enum NodeTypeID getNodeID() {
static NodeTypeID lastID = 0;
return lastID++;
}
enum NodeTypeID getNodeID(T)() {
static NodeTypeID typeID = getNodeID();
return typeID;
}
-------------------------------------------------------------------------------
The expectation is that this is executed at compile time,
generating a specific function for the given generic parameter
each time the generic is used, incrementing the static variable
by 1 and having the compiled generic functions essentially
contain magic number unique to its type. So, I would be able to
employ this like so:
-------------------------------------------------------------------------------
switch (someNodeTypeID) {
case getNodeID!(Sprite)(): // Sprite node-specific behavior.
break;
case getNodeID!(Camera)(): // Camera node-specific behavior.
break;
default: // Default behavior.
break;
}
-------------------------------------------------------------------------------
However, I've been struggling with an error pertaining to
getNodeType. The return statement of lastID++ is flagging the
error
"Static variable cannot be read at compile time."
I may just be taking too much of a C++ lens to this, but to me
this seems like it should work? Am I missing a qualifier or
something here?
