Returns true if there are no more events
Due to the wonders of DTDs, an entity declaration can be just about anything. There’s no way to normalize it; you’ll have to interpret the content yourself. However, the following is true:
Content: [ String
text ]
Content: [ String
text ]
| AdditiveExpr
(‘+’ | ‘-’) MultiplicativeExpr
| MultiplicativeExpr
| LocationPath
| FilterExpr
(‘/’ | ‘//’) RelativeLocationPath