xsl:key with sequence-constructor instead of @use-attribute ist not handeled by skeleton correctly

[hschmull]

As pointed out in #42 xsl:key should be used in Schematron without restrictions.

When I use an xsl:key with a sequence-constructor as content instead of a @use-attribute I get the error:

An xsl:key element must either have a @use attribute or have content

seems the content is ignored by skeleton. When I rewrite my key, putting the sequence-constructor in an xsl:function and refer it in a @use-attribute ecerythin works as expected.

My Example:

	<xsl:key name="verzeichnisse" match="/projekt/werk//
		*[local-name() = ('bild','formel','tabelle','video','audio','popup_inline') or meta/nachweis]
		[not(self::ausgabe_verzeichnis | self::ausgabe_index | self::ausgabe_definitionen | ancestor::alternativinhalt)]">
		<xsl:choose>
			<xsl:when test="self::bild[not( @verzeichnis = ('nein', 'tabelle', 'formel') )]
				|  (self::formel | self::tabelle)[@verzeichnis = 'abbildung']">
				<xsl:sequence select="'abbildung'"/>
			</xsl:when>
			<!-- ... -->
			<xsl:when test="self::video | self::audio | self::popup_inline">
				<xsl:sequence select="local-name()"/>
			</xsl:when>
		</xsl:choose>
	</xsl:key>

does not work, but:

	<xsl:key name="verzeichnisse" match="/projekt/werk//
		*[local-name() = ('bild','formel','tabelle','video','audio','popup_inline') or meta/nachweis]
		[not(self::ausgabe_verzeichnis | self::ausgabe_index | self::ausgabe_definitionen | ancestor::alternativinhalt)]" use="pa:keyVerzeichnis(.)"/>
		
	<xsl:function name="pa:keyVerzeichnis">
		<xsl:param name="element" as="element()"/>
		<xsl:choose>
			<xsl:when test="$element/(self::bild[not( @verzeichnis = ('nein', 'tabelle', 'formel') )]
				|  (self::formel | self::tabelle)[@verzeichnis = 'abbildung'])">
				<xsl:sequence select="'abbildung'"/>
			</xsl:when>
			<!-- ... -->
			<xsl:when test="$element/(self::video | self::audio | self::popup_inline)">
				<xsl:sequence select="$element/local-name()"/>
			</xsl:when>
		</xsl:choose>
	</xsl:function>

does – which took a bit of otherwise unnecessary refactoring.

[dmj]

I added a conformance test for this: Schematron/schematron-conformance@71b8468

[hschmull]

Thank you, David.