class ELT_NIL{ETP} |
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**** | Provides the nil value for an object of type ETP. If ETP < $NIL then return ETP::nil otherwise return void This does not work for abstract types - hence, abstract classes should not be placed under $NIL |
elt_nil: ETP |
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**** | Return the nil value. If the element is under $NIL then return e.nil. Otherwise, return "void" |
is_elt_nil(e:ETP):BOOL |
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**** | Return true if ETP is defines a nil value and "e" has that value or if ETP does not define a nil value, but "e" is void |