Bug #6519
closed
Confusing documentation for otherwise
0%
Description
By way of a question on the. XML.com slack, on the page about otherwise we find:
The precedence of the operator is greater than arithmetic operators (so $n div $m otherwise 1 means $n div ($m otherwise 1)), but less than the "union" operator (so a/b/c otherwise 0 means (a/b/c) otherwise 0).
But there isn't an obvious use of the union operator there. Was that meant to be (a|b|c) otherwise 0?
Updated by Michael Kay 3 months ago
Rephrasing this for 12.x as
As defined in the current XPath 4.0 draft (September 2024), arithmetic operators such as +
bind more tightly than otherwise, so $a + $b otherwise $c
means ($a + $b) otherwise $c. However, Saxon 12 implements an earlier draft of the
specification in which it means $a + ($b otherwise $c). Use parentheses to make your
intended meaning clear and to avoid compatibility problems in the future.
This deliberately avoids describing the exact implemented precedence in 12.x; what people need to know is that it's going to change so they need to use parentheses.
Updated by Michael Kay 3 months ago
- Category set to Documentation
- Status changed from New to Resolved
- Assignee set to Michael Kay
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