anchor.diff:  * We assume the common graphical order over unicode strings.
   * LHS and RHS needs to be lexicographically equal for LHS eq RHS == TRUE for String.
   
  +===== UUID
  +* UUID is evaluated based on its String representation.
  +* However, for example, UUID("b46d37e9-755c-477e-9ab6-44aabea51d50") and String "b46d37e9-755c-477e-9ab6-44aabea51d50" are not equal to oeach other.
  +
   ===== Date
   
   * If either one of LHS or RHS is Date and another isn't, return FALSE
  
positive.code: ===== String
  * String value is ordered lexicographically
  
  ===== Date
  * Date value is ordered chronologically
  
  
negative.code: * Which should be more reasonable, NULL eq NULL is true or false ?
    ** If it is true, it may be respected in JOIN operation
  * There are a number of situations where the Gremlin grammar won’t support some of the examples - to what extent do these sorts of constructs need to exist in the grammar? Not having them would impact the ability to supply tests that enforce the behaviors that we’ve outlined. 
  
  == Technical Appendix
  
  