Writing Attribute Values

There are several ways to write attribute values to output documents in XSLT, and the most powerful one is to create attributes from scratch with the <xsl:attribute> element youll see in Chapter 6. However, you can also use attribute value templates for many purposes, and Ill take a look at them in this chapter.

For example, suppose that you want to convert the text in the elements such as <MASS> , <DAY> , and < NAME > to attributes of <PLANET> elements, converting planets.xml to this form:

 <?xml version="1.0" encoding="UTF-8"?>  <PLANETS>      <PLANET DAY="58.65 days" RADIUS="1516 miles"          MASS=".0553 (Earth = 1)" NAME="Mercury"/>      <PLANET DAY="116.75 days" RADIUS="3716 miles"          MASS=".815 (Earth = 1)" NAME="Venus"/>      <PLANET DAY="1 days" RADIUS="2107 miles"          MASS="1 (Earth = 1)" NAME="Earth"/>  </PLANETS>

To create the transformation, you cant just use expressions such as the following, where I take the values of the <NAME> , <MASS> , and <DAY> elements and try to make them into attribute values:

 <xsl:template match="PLANET">      <PLANET NAME="<xsl:value-of select="NAME"/>"          MASS="<xsl:value-of select="MASS"/>"          DAY="<xsl:value-of select="DAY"/>"      />

This doesnt work, because you cant use < inside attribute values as I have in the preceding example. XLST provides multiple ways to do that, however. One way is to use attribute value templates.