before the ThemeMetric templates that use them. That's broken
and unreasonable, so change this around a bit and make FromStack
(and Push) templates.
Push() takes a bit of a trick. Some Push overloads push the
actual value: scalars (int, float), RageColor (pushes a table).
Others--most of them--push a reference to a C++ object. We
want the scalars to have a reference parameter type, so we
don't make extra copies of things like RageColor when we push
them. We need to pass C++ objects by pointer (we need to
push the actual object's pointer, not a pointer to a copy).
Further, pushing a scalar is a const operation, but pushing
a reference to an object is not.
To do both with the same template, we handle objects with
this slightly odd template:
template<> void LuaHelpers::Push<T*>( lua_State *L, T *const &pObject );
The actual overload (T) is eg. "Actor*"; this fits within the
general prototype, "Push(lua_State *L, const T &object)", giving
us a const reference to a (non-const) pointer to Actor, and we're
conceptually pushing the pointer.
The net effect of this is that 1: what was before compile errors
now becomes link time errors, but 2: these specializations
don't have to be in the headers (except for new ones for
Preference and BroadcastOnChange).
Glenn Maynard