Thanks. As I say, I'm cleaning up legacy code that has a lot of mess in it, and
in fact a try/catch isn't the solution I'll be using to avoid the problem in
this case; I was just curious about the (in)ability of try/catch to prevent
duplicate attributes within an element constructor. Clearly there are better
ways to prevent them than relying on that.
David
On Thu, 19 Dec 2013, Ryan Dew wrote:
Adding to this, my personal opinion is that try/catches should be a last
resort and you'll be a better programmer for avoiding them. Not to mention,
you can often see performance increases by avoiding them if the code is
something that is called repeatedly and are less likely to unintentionally
mask problems. For example you can do the following (please excuse the
formatting):
xquery version "3.0";
let $element := <el att1="one" att2="two" id="old-id">text</el>
return element new {
$element/attribute(),
if (fn:empty($element/@id)) then attribute id { "new-id" } else (),
$element/node()
}
On Thu, Dec 19, 2013 at 11:31 AM, Christian Grün
<[email protected]>wrote:
Hi David,
[…]
try {attribute id { "new-id" }} catch * {()},
[…]
but it doesn't trap the error (in any XQuery 3 processor I've checked).
The
try/catch will work only if put around the entire element constructor.
The reason for this is that the attribute constructor itself is
correct. The error occurs when trying to add the newly created
attribute to the element.
The following query should work:
let $element := <el att1="one" att2="two" id="old-id">text</el>
return element new {
$element/attribute(),
if($element/@id) then () else attribute id { "new-id" },
$element/node()
}
Hope this helps,
Christian
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ROTUNDA, The University of Virginia Press
PO Box 400314, Charlottesville, VA 22904-4314 USA
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