XSLT2 doesn't import user functions? - import

Question

I've just found that if main.xsl xsl:imports lib.xsl which defines some XSLT2 functions, those functions can't be used in main.xsl.
Error: There's no function in namespace http://foo.bar/my-library-ns
However, xsl:include does import those functions.

Answer 1

This is no reproducible
This stylesheet:
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:local="http://localhost/">
<xsl:import href="lib.xsl"/>
<xsl:template match="/">
<xsl:value-of select="local:function()"/>
</xsl:template>
</xsl:stylesheet>
With this imported module:
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:local="http://localhost/"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xsl:function name="local:function" as="xs:boolean">
<xsl:sequence select="true()"/>
</xsl:function>
</xsl:stylesheet>
Output*:
true
* Tested on Saxon and Altova. (My XQSharp has expired...)

Answer 2

I've just found that if main.xsl
xsl:imports lib.xsl which defines some
XSLT2 functions, those functions can't
be used in main.xsl
Of course, this isn't true.
Do have a look at the FXSL library, whose templates contain functions that must be imported by the using XSLT code. The stylesheet modules of FXSL in fact import other stylesheet modules and use their functions.
Here is a simple example:
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:f="http://fxsl.sf.net/"
exclude-result-prefixes="f"
>
<xsl:import href="../f/func-foldl.xsl"/>
<xsl:import href="../f/func-Operators.xsl"/>
<!--
This transformation calculates 10!
Expected result: 3628800 or 3.6288E6
-->
<xsl:output encoding="UTF-8" omit-xml-declaration="yes"/>
<xsl:template match="/">
<xsl:value-of select="f:foldl(f:mult(), 1, 1 to 10 )"/>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied on any XML document (not used), it calculates the 10! (10 factorial) value:
3628800
All three XSLT 2.0 processors I am working with: Saxon 9, AltovaXML and XQSharp produce this same result.
Here is a partial view at the import hierarchy of the above transformation:
As we can see, only less than half of all imports are shown... :)
Of course here we only see the imported templates, but in every imported stylesheet module, for every template there are at least two <xsl:function>s.