Don't allow huge varNames

[alexewerlof]

due to the risk for DDoS put a limit on how long the var names can be.
A deeply nested very long var name can potentially DDoS the user's code.
Initially the limit can be 1000 characters which using the a.b.c.d... syntax can lead to a maximum depth of 500 lookups.

[alexewerlof]

Maybe the initial limit can be lower (140 chars), but allow changing it using an option. That way the limit is not hard coded and the users can opt-in to something that makes sense to them.