Evaluation of Filters
When filters are combined with the binary operators, unary operators, or both, they are evaluated according to these rules:
- First, evaluate the contents of parentheses.
- Next, evaluate filters that use unary operators. Both SKIP and WHILE operators have the same precedence.
- Finally, evaluate filters that use the binary operators. AND has higher precedence than OR.
For
example, in a filter of the form Filter1 AND Filter2 OR
Filter
, Filter1 AND Filter2
is evaluated and
the result is X. Then, X
OR Filter3
is evaluated.
For
another example, a filter of the form Filter1 AND SKIP
Filter2 OR Filter3
is evaluated in these steps:
-
Evaluate
SKIP Filter2
with the result being X. -
Evaluate
Filter1 AND
X with the result being Y. -
Evaluate
Y
OR Filter3
.