static int _as(lua_State *L)
{
// as of null returns null
if (lua_isnil(L, 1))
{
lua_pushnil(L);
return 1;
}
// get the assembly lookup table
lua_rawgeti(L, LUA_GLOBALSINDEX, LSASSEMBLYLOOKUP);
// push the (interned) assembly name
lua_pushvalue(L, 2);
lua_gettable(L, -2);
// get the Assembly*
Assembly *assembly = (Assembly *)lua_topointer(L, -1);
lua_pop(L, 2);
lmAssert(assembly, "Object::_as - unable to get Assembly");
LSLuaState *lstate = assembly->getLuaState();
// the castType is the type we're casting to
Type *castType = assembly->getTypeByOrdinal((LSTYPEID)lua_tonumber(L, 3));
lmAssert(castType, "Object::_as - unable to resolve TypeID %u", (LSTYPEID)lua_tonumber(L, 3));
// checking number -> enum coercian
if (lua_isnumber(L, 1))
{
if (castType->isEnum())
{
lua_pushvalue(L, 1);
return 1;
}
}
bool valid = false;
if (castType == lstate->numberType)
{
if (lua_isnumber(L, 1))
{
valid = true;
}
}
else if (castType == lstate->stringType)
{
if (lua_isstring(L, 1))
{
valid = true;
}
}
else if (castType == lstate->booleanType)
{
if (lua_isboolean(L, 1))
{
valid = true;
}
}
else if (castType == lstate->functionType)
{
if (lua_iscfunction(L, 1))
{
valid = true;
}
else if (lua_isfunction(L, 1))
{
valid = true;
}
}
else
{
// If it's a primitive type but we expected an instance table, it is nil.
valid = true;
if (lua_isnumber(L, 1))
{
valid = false;
}
else if (lua_isstring(L, 1))
{
valid = false;
}
else if (lua_isboolean(L, 1))
{
valid = false;
}
else if (lua_iscfunction(L, 1))
{
valid = false;
}
else if (lua_isfunction(L, 1))
{
valid = false;
}
if (valid)
{
// If we are not a primitive type (as detected previously)
// we should be an instance table, if not something went horribly wrong
if (!lua_istable(L, 1))
{
lua_pushfstring(L, "Object._as - instance table expected but got %s", lua_typename(L, 1));
lua_error(L);
}
// retrieve the instance's type
lua_rawgeti(L, 1, LSINDEXTYPE);
Type *type = (Type *)lua_topointer(L, -1);
lmAssert(type, "error getting type in Object._as");
lua_rawgeti(L, 1, LSINDEXDELETEDMANAGED);
if (lua_toboolean(L, -1) == 1)
{
lua_pushfstring(L, "Object._as - accessing deleted managed native instance of type %s", type->getFullName().c_str());
lua_error(L);
}
lua_pop(L, 1);
// we're the same type, so push identity and return
if (castType == type)
{
lua_pushvalue(L, 1);
return 1;
}
// if we're native types, C++ RTTI can be used
if (type->isNative() && castType->isNative())
{
// get the native user data from the instance
lua_rawgeti(L, 1, LSINDEXNATIVE);
assert(lua_isuserdata(L, -1));
Detail::Userdata *ptr = (Detail::Userdata *)lua_topointer(L, -1);
// push the instance on the stack, possibly downcasting it
NativeInterface::pushDynamicCast(L, type, castType, 1, ptr->getPointer());
return 1;
}
valid = type->castToType(castType) ? true : false;
}
}
if (valid)
{
lua_pushvalue(L, 1);
}
else
{
lua_pushnil(L);
}
return 1;
}
