XSL / Вывод брендов с разбивкой по алфавиту

XSL шаблон, который выводит бренды из модуля интернет-магазина, разделяя их по алфавиту

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE xsl:stylesheet>
<xsl:stylesheet version="1.0"
	xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
	xmlns:hostcms="http://www.hostcms.ru/"
	exclude-result-prefixes="hostcms">
	<xsl:output xmlns="http://www.w3.org/TR/xhtml1/strict" doctype-public="-//W3C//DTD XHTML 1.0 Strict//EN" encoding="utf-8" indent="yes" method="html" omit-xml-declaration="no" version="1.0" media-type="text/xml"/>
	
	<xsl:key name="a" match="shop_producer" use="substring(name, 1, 1)" />
	
	
	<!-- МагазинСписокПроизводителей -->
	
	<xsl:template match="/">
		<section id="produsers">
			<xsl:apply-templates select="shop"/>
		</section>
	</xsl:template>
	
	<xsl:template match="shop">
		
		<div class="top">
			<h1>Бренды</h1>
		</div>
		
		<xsl:if test="count(shop_producer) = 0">
			<div id="error">Производители не найдены!</div>
		</xsl:if>
		
		<div class="block3" style="padding: 5px 0 12px 5px;">
			<div class="row">
				<ul>
					<xsl:apply-templates select="shop_producer" mode="alphabet">
						<xsl:sort select="name" order="ascending"/>
					</xsl:apply-templates>
				</ul>
			</div>
			
			<!--xsl:apply-templates select="shop_producer">
			<xsl:sort select="name" order="ascending"/>
		</xsl:apply-templates-->
	</div>
</xsl:template>

<xsl:template match="shop_producer" mode="alphabet">
	<xsl:variable name="a" select="substring(name,1,1)"/>
	<xsl:if test="not(preceding-sibling::shop_producer[starts-with(name, $a)][1])">
		<li class="col-xs-12">
			<h4><xsl:value-of select="$a"/></h4>
			
			<div class="row">
				<ul>
					<xsl:for-each select="/shop/shop_producer">
						<xsl:variable name="name" select="substring(name,1,1)"/>
						<xsl:if test="$a = $name">
						<li class="col-xs-6 col-sm-4 col-md-3 match-height"><a class="producer" href="{/shop/url}producer-{@id}/"><xsl:value-of disable-output-escaping="no" select="name"/></a></li>
						</xsl:if>
					</xsl:for-each>
				</ul>
			</div>
		</li>
	</xsl:if>
</xsl:template>

<xsl:template match="shop_producer">
	<a class="producer" href="{/shop/url}producers/{path}/"><xsl:value-of disable-output-escaping="no" select="name"/></a>
</xsl:template>

</xsl:stylesheet>