[x3d-public] Request for X3D encoding comment output from X3DPSAIL

Mon Jan 5 11:43:03 PST 2026

What comment parsing requires in Java SAXParser is handling the comment
method in a subclass of DefaultHandler2:

https://docs.oracle.com/javase/8/docs/api/org/xml/sax/ext/DefaultHandler2.html

This should be handy enough to replace newlines inside an attribute inside
a comment different from other newlines in a comment.

Not ideal yet. Feel free to deploy extra test cases while “code” it up.

John

On Sun, Jan 4, 2026 at 4:01 PM John Carlson <yottzumm at gmail.com> wrote:

> My current plan for replacing multiple line comments with single lines
> comments where the comment content are preserved on separate lines is as
> follows:
>
> 1.  Write a Java SAX parser to replace newlines with —>\n<!— inside XML
> comments.
>
> 2.  Compile with GraalVM native-image into rnl.exe, if not taken.
>
> Write a script to apply to all original .x3d files in my examples.  This
> will call vim or ex (vim command-line), with the command, %!rnl.exe, then
> save and exit.
>
> If needed, I will include carriage return.
>
> Others would try to make this a stylesheet, but I don’t know if comment()
> can be split on newlines in XSLT.   So I’ll ask claude.ai again!
>
> <xsl:stylesheet version="2.0" xmlns:xsl="
> http://www.w3.org/1999/XSL/Transform">
>
> <xsl:template match="@*|node()">
> <xsl:copy>
> <xsl:apply-templates select="@*|node()"/>
> </xsl:copy>
> </xsl:template>
>
> <xsl:template match="comment()">
> <xsl:for-each select="tokenize(., '&#xA;')">
> <xsl:if test="normalize-space(.) != ''">
> <xsl:comment><xsl:value-of select="normalize-space(.)"/></xsl:comment>
> </xsl:if>
> </xsl:for-each>
> </xsl:template>
>
> </xsl:stylesheet>
>
> Gobbledegook to me, but maybe someone can use it.
>
> John
>
> On Sun, Jan 4, 2026 at 3:32 PM John Carlson <yottzumm at gmail.com> wrote:
>
>> For example, it nearly requires program to do this in Python or Perl.
>>
>> Claude.ai reports:
>>
>> perl -i -0pe 's/<!--(.*?)-->/join("\n", map {"<!-- $_ -->"} grep
>> {s|^\s*||; s|\s*$||; $_} split("\n", $1))/gse' file.xml
>>
>> Obviously I can put this in a shell script, but I like stuff I can
>> understand!
>>
>> Something in Java would be great!  Maybe I’ll write and contribute if it
>> doesn’t already exist?
>>
>> Seems like a simple SAX parser, frankly!
>>
>> John
>>
>> On Sun, Jan 4, 2026 at 3:10 PM John Carlson <yottzumm at gmail.com> wrote:
>>
>>> Thanks, it wasn’t clear to me that multi-line comments were not
>>> supported in X3D XML encoding.  That clears up most of my questions!
>>>
>>> I will replace multi-line comments with single-line comments in my
>>> examples.   Does X3D-Edit support this feature?  This would be great, and
>>> encourage me to use it!
>>>
>>> John
>>>
>>> On Sun, Jan 4, 2026 at 2:46 PM Don Brutzman <don.brutzman at gmail.com>
>>> wrote:
>>>
>>>> For clarity, here is a recap of key points that can be found in prior
>>>> responses and ticket issues:
>>>>
>>>>    - Persistent single-line comments are an important feature for X3D
>>>>    model conversions and interoperability.
>>>>    - You are welcome to use all Python features, including multi-line
>>>>    comments, whenever programming with Python and x3d.py.
>>>>    - Individual multi-line comments are not supported in a number of
>>>>    file encodings and programming languages.  Nor are they defined by X3D
>>>>    Architecture, nor are they supported by several X3D encodings (such as XML
>>>>    and ClassicVRML).  Thus multi-line comments are not a required feature.
>>>>    - Persistent comments in x3d.py Python are already supported via a
>>>>    Comment class.
>>>>    - Persistent single-line comments are now partially supported by
>>>>    X3dToPython.xslt converter, if present as children of Scene head and
>>>>    grouping nodes.  Further future work on content-model representations in
>>>>    the Python class hierarchy may be able to add them elsewhere (e.g. inside
>>>>    Shape Appearance Material geometry etc.
>>>>    - Tickets are closed after careful review if they are unrepeatable
>>>>    or unactionable.  Suggestions and questions about a clearer ticket are
>>>>    usually included.
>>>>
>>>> Hope this helps.
>>>>
>>>> all the best, Don
>>>> --
>>>> X3D Graphics, Maritime Robotics, Distributed Simulation
>>>> Relative Motion Consulting  https://RelativeMotion.info
>>>>
>>>>
>>>> On Sun, Jan 4, 2026 at 5:57 AM John Carlson <yottzumm at gmail.com> wrote:
>>>>
>>>>> Blowing off some steam.  Apologies, I probably should work out instead.
>>>>>
>>>>> I am unsure if it’s easier to output straight line code instead of
>>>>> hierarchical code in Python; multi-line non-persistent comments might
>>>>> become easier in straight line code.  I don’t know about comments() in
>>>>> XSLT.  In straight line code, wrapping a multi or single line comment in
>>>>> “””…””” is a cinch.  Even if newlines need to be added for the Python
>>>>> interpreter.
>>>>> AFAIK, I’ve already mentioned that straight line code is easier to
>>>>> debug, in my mind.  I think the Java large file discussion is still
>>>>> open; I know hierarchical code is more succinct, and less likely to stack
>>>>> overflow.  I think the choices between code structure in Python and Java
>>>>> might be different.
>>>>>
>>>>> Persistent multi-line comments are desirable, even if they aren’t
>>>>> present in the archive.  We will probably make different choices between
>>>>> hierarchical and straight line code when this feature is available.
>>>>>
>>>>> Short term hacks like single line comments work until features are
>>>>> introduced.  That doesn’t mean tickets should be closed prematurely, or
>>>>> examples outside the archives are invalid.
>>>>>
>>>>> John
>>>>>
>>>>> On Tue, Dec 30, 2025 at 3:42 AM John Carlson <yottzumm at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Don, thanks for your comment on this ticket that naively adding
>>>>>> Comment to a children field might not work.  That was one of my intentions
>>>>>> on expressing myself so vocally.  I apologize for using your time to do
>>>>>> this, but I think it revealed a possible design consideration.  I think if
>>>>>> I had discovered it, it would have gone over like a wet balloon.
>>>>>>
>>>>>> Thank you again, I will not put comments arbitrarily in the
>>>>>> scenegraph for now with my PythonSerializer.js, until you indicate it’s
>>>>>> ready!   I will leave them out of the scenegraph, as they are now.   Since
>>>>>> I handle comments generically, I will have to research the nodes you’ve
>>>>>> accomplished.
>>>>>>
>>>>>> Now, can we have other multi-line comments, not in the persistent
>>>>>> scenegraph, in Python translated from .x3d, in the short term, like:
>>>>>>
>>>>>> #
>>>>>> # This is comment line 2
>>>>>> # This is comment line 3
>>>>>> #
>>>>>>
>>>>>> ?
>>>>>>
>>>>>> John
>>>>>>
>>>>>> From the ticket:
>>>>>>
>>>>>> “
>>>>>>
>>>>>> This is not an easy fix for converting files because Comment is not
>>>>>> part of the content model for all nodes. Solving this will probably require
>>>>>> extending class _ X3DNode in x3d.py and sorting out possible subclass
>>>>>> collisions. It will also be difficult to retain the original order of child
>>>>>> nodes and child comments within a parent node.
>>>>>>
>>>>>> This might be fixable someday - after some effort I got it working
>>>>>> for head, Scene, field, fieldValue.. Deferred as future work.
>>>>>>  ”
>>>>>>
>>>>>> On Mon, Dec 29, 2025 at 12:52 PM Don Brutzman <don.brutzman at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>>
>>>>>>> I have posted a new ticket to capture this point.  Perhaps a useful
>>>>>>> exemplar, as well.
>>>>>>>
>>>>>>>    - X3D SourceForge ticket #82 creating persistent comments in
>>>>>>>    python when converting from XML
>>>>>>>    - https://sourceforge.net/p/x3d/tickets/82/
>>>>>>>
>>>>>>> Hope this helps.  Again thanks for your many efforts.  Have fun
>>>>>>> improving X3D!  🤔 👍
>>>>>>>
>>>>>>>>
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