ll.LinksetDataRead("key") and ll.LinksetDataReadProtected("key", "pass") both will return an empty string if trying to access a stored value that doesn't exist. Which is not "nil".
Can we get it so that if a key pair does not exist in the LSD store that the return is actually a "nil" type instead? It would also return nil on a protected key with a bad "pass".
We have access to the nil data type with SLua now, and it'd be more logical for a non-existent key to return nil for a simple boolean test. IMO. Just an idea at least.
Added thought:
maybe have "llcompat" have the return still be a zero length ("") string for, well, compatibility sake.