用XSLT编写JSON

我正在尝试编写XSLT来将特定的网页转换为JSON.以下代码演示了Ruby如何进行此转换，但是XSLT不会生成有效的JSON(数组中有太多逗号)-有人知道如何编写XSLT来生成有效的JSON吗?

I'm trying to write XSLT to transform a specific web page to JSON. The following code demonstrates how Ruby would do this conversion, but the XSLT doesn't generate valid JSON (there's one too many commas inside the array) - anyone know how to write XSLT to generate valid JSON?

require 'rubygems'
require 'nokogiri'
require 'open-uri'

doc = Nokogiri::HTML(open('http://bbc.co.uk/radio1/playlist'))
xslt = Nokogiri::XSLT(DATA.read)

puts out = xslt.transform(doc)

# Now follows the XSLT
__END__
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns="http://www.w3.org/1999/xhtml">
    <xsl:output method="text" encoding="UTF-8" media-type="text/plain"/>

    <xsl:template match="/">
        [
        <xsl:for-each select="//*[@id='playlist_a']//div[@class='artists_and_songs']//ul[@class='clearme']">
            {'artist':'<xsl:value-of select="li[@class='artist']" />','track':'<xsl:value-of select="li[@class='song']" />'},
        </xsl:for-each>
        ]
    </xsl:template>
</xsl:stylesheet>