[x3d-public] No mutable maps in Saxon; DEF/USE solution?

[John Carlson]

Untested XSLT 1.0 and 2.0. YMMV!

Prompt:

in XSLT, how do I find the first node with an attribute with a the name
USE, but the same value as and before a node with the attribute with the
name DEF. Swap the two nodes, then do this for all nodes that have DEF and
USE. The nodes swapped should have the same tag.

Response:

This is the
*identity-transform-with-selective-swap* if you’re not going to use AI.


https://claude.ai/share/ea29239f-adc6-4dbd-b84c-a49ba8413c83

Please test thoroughly if you’re going to use this.  And use proper
attribution, of course!

Hoping that we can see something like this soon, I might try it in my
pipeline, if no one else cares to try it.  But I would have to dig into the
guts of X3DJSAIL, and that stylesheet is super scary!

John

On Sat, Mar 28, 2026 at 3:28 AM John Carlson <yottzumm at gmail.com> wrote:

> Finding nodes before or after a node in XSLT.  Google search.
>
> John
>
>
>
> On Sat, Mar 28, 2026 at 3:17 AM John Carlson <yottzumm at gmail.com> wrote:
>
>> path() in XSLT:
>>
>> https://stackoverflow.com/questions/38602029/generate-xpath-from-node-using-xslt-2#:~:text=Comments,-Add%20a%20comment&text=A%20couple%20of%20points.,element%20names%20are%20context%2Dfree.
>>
>> Read Michael Kay’s comment before using his code….
>>
>> On Sat, Mar 28, 2026 at 2:59 AM John Carlson <yottzumm at gmail.com> wrote:
>>
>>> The issue with why there’s no DEF/USE reordering in X3DJSAIL and
>>> X3DPSAIL apparently stems from Saxon not being able to handle mutable
>>> maps/lookup tables.  So let’s build a map per scene, but don’t build it in
>>> the X3dTo….xslt, but as a generated XSLT map, perhaps in another file,
>>> XSLT or not.
>>>
>>> Perhaps we need to write a preprocessor to map DEF/USE values to a list
>>> of XPath expressions in a file per XML scene which allows the DEF node and
>>> first USE node for a particular DEF value to be found with an XPath.  If
>>> the DEF node isn’t the first XPath for a given DEF/USE value, then the DEF
>>> node is swapped with the first USE node with the same DEF value.  We can
>>> probably export this as a stylesheet per XML scene.
>>>
>>> Will this actually work?
>>>
>>> Criticism welcome!
>>>
>>> I’d say Don could probably whip this up really quick if he can retrieve
>>> XPaths for all DEF and USE nodes in a scene.  Maybe Vince could as well.
>>> What implementation language do we use?
>>>
>>> Do PROTOs affect this?
>>>
>>> Sorry for all the emails today!
>>>
>>> I finally got outside the box as they used to say.
>>>
>>> John
>>>
>>
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