Whitespace in xsl text transformation - xslt

Question

A XSLT with a xsl:text containing a single (or multiple) whitespace(s) is not printing the whitespace(s) in MarkLogic 9.0-9. See the following example:
xquery version "1.0-ml";
let $doc :=
<doc>
<foo>foo</foo>
<bar>bar</bar>
</doc>
let $xsl :=
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="2.0">
<xsl:output method="text" omit-xml-declaration="yes" indent="no" />
<xsl:template match="doc">
<xsl:value-of select="foo"/>
<xsl:text> </xsl:text>
<xsl:value-of select="bar"/>
</xsl:template>
</xsl:stylesheet>
return xdmp:xslt-eval($xsl, $doc) = "foo bar"
This returns false. The result is "foobar". I actually expected "foo bar".
I also tried with <xsl:text xml:space="preserve"> </xsl:text> but this does not work either.
As a workaround I currently use <xsl:value-of select="' '"/> which works fine but I am wondering if this is a bug? Using the same transformation and document in Saxon prints the whitespaces.

Answer 1

For standard XQuery you should get what you want with
declare boundary-space preserve;
in the query prolog, see https://www.w3.org/TR/xquery-31/#id-boundary-space-decls and https://www.w3.org/TR/xquery-31/#id-whitespace.
Example is https://xqueryfiddle.liberty-development.net/eiQZDbq/4 doing
declare boundary-space preserve;
declare namespace output = "http://www.w3.org/2010/xslt-xquery-serialization";
declare option output:method 'text';
let $doc :=
<doc>
<foo>foo</foo>
<bar>bar</bar>
</doc>
let $xsl :=
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="2.0">
<xsl:output method="text" omit-xml-declaration="yes" indent="no" />
<xsl:template match="doc">
<xsl:value-of select="foo"/>
<xsl:text> </xsl:text>
<xsl:value-of select="bar"/>
</xsl:template>
</xsl:stylesheet>
return transform(map { 'source-node' : $doc, 'stylesheet-node' : $xsl })?output
returning foo bar while https://xqueryfiddle.liberty-development.net/eiQZDbq/2 without that declaration returns foobar.
I have not checked whether Marklogic supports that declaration or some proprietary similar way to change parsing treatment of whitespace in element constructors.