Preserve character hex codes during XSLT 2.0 transform

Question

I have the following XML:

<root>
   <child value="&#xFF;&#xEF;&#x99;&#xE0;"/>
</root>

When I do a transform I want the character hex code values to be preserved. So if my transform was just a simple xsl:copy and the input was the above XML, then the output should be identical to the input.

I have read about the saxon:character-representation function, but right now I'm using Saxon-HE 9.4, so that function is not available to me, and I'm not even 100% sure it would do what I want.

I also read about use-character-maps. This seems to solve my problem, but I would rather not add a giant map to my transform to catch every possible character hex code.

<xsl:character-map name="characterMap">
    <xsl:output-character character="&#xA0;" string="&amp;#xA0;"/>
    <xsl:output-character character="&#xA1;" string="&amp;#xA1;"/>
    <!-- 93 more entries... &#xA1; through &#xFE; -->
    <xsl:output-character character="&#xFF;" string="&amp;#xFF;"/>
</xsl:character-map>

Are there any other ways to preserve character hex codes?

Answer 1

The XSLT processor doesn't know how the character was represented in the input - that's all handled by the XML parser. So it can't reproduce the original.

If you want to output all non-ASCII characters using numeric character references, regardless how they were represented in the input, try using xsl:output encoding="us-ascii".

If you really need to retain the original representation - and I can't see any defensible reason why anyone would need to do that - then try Andrew Welch's lexev, which converts all the entity and character references to processing instructions on the way in, and back to entity/character references on the way out.