trueif the object or entity is external, and
isntreverses the results.
stream-name indexer? (is | isnt) externalor
entity (is | isnt) external
This keyword tests to determine whether the object attached to a stream is external (an externally defined output stream). It returns true if the object is external, and
false otherwise. Replacing
isnt will reverse the results.
It can also be used as an entity test that returns true if the entity is an external entity. In this form, it is used primarily when testing the entities named by the values of
entities attributes. This test will always be true in an