The xsl:processing-instruction Element: Generating Processing Instructions

The <xsl:processing-instruction> Element: Generating Processing Instructions

You can create new processing instructions with the <xsl:processing-instruction> element. This element has one attribute:

name (mandatory). Sets the name of the processing instruction. Set to an attribute value template that returns an NCName.

In the following example, Ive removed the <?xml-stylesheet?> instruction from the beginning of planets.xml:

 <?xml version="1.0"?>  <PLANETS>      <PLANET>          <NAME>Mercury</NAME>          <MASS UNITS="(Earth = 1)">.0553</MASS>          <DAY UNITS="days">58.65</DAY>          <RADIUS UNITS="miles">1516</RADIUS>          <DENSITY UNITS="(Earth = 1)">.983</DENSITY>          <DISTANCE UNITS="million miles">43.4</DISTANCE><!--At perihelion-->      </PLANET>      <PLANET>          <NAME>Venus</NAME>          <MASS UNITS="(Earth = 1)">.815</MASS>          <DAY UNITS="days">116.75</DAY>          <RADIUS UNITS="miles">3716</RADIUS>          <DENSITY UNITS="(Earth = 1)">.943</DENSITY>          <DISTANCE UNITS="million miles">66.8</DISTANCE><!--At perihelion-->      </PLANET>          .          .          .

To add that processing instruction again, you can use the <xsl:processing-instruction> element. The type and href items in a processing instruction such as <?xml-stylesheet type="text/xml" href="planets.xsl"?> are not actually attributes, so rather than set their values with <xsl:attribute> , you use simple text:

Listing 6.9 Using <xsl:processing-instruction>

 <?xml version="1.0"?>  <xsl:stylesheet version="1.0"  xmlns:xsl="http://www.w3.org/1999/XSL/Transform">  <xsl:output method="xml"/>    <xsl:template match="/">      <xsl:processing-instruction name="xml-stylesheet">          <xsl:text>type="text/xml" href="planets.xsl"</xsl:text>      </xsl:processing-instruction>      <xsl:apply-templates/>    </xsl:template>    <xsl:template match="@*node()">      <xsl:copy>        <xsl:apply-templates select="@*node()"/>      </xsl:copy>    </xsl:template>  </xsl:stylesheet>

Heres the result, where you can see the <?xml-stylesheet?> processing instruction back in place:

 <?xml version="1.0" encoding="UTF-8"?>  <?xml-stylesheet type="text/xml" href="planets.xsl"?>  <PLANETS>      <PLANET>          <NAME>Mercury</NAME>          <MASS UNITS="(Earth = 1)">.0553</MASS>          <DAY UNITS="days">58.65</DAY>          <RADIUS UNITS="miles">1516</RADIUS>          <DENSITY UNITS="(Earth = 1)">.983</DENSITY>          <DISTANCE UNITS="million miles">43.4</DISTANCE><!--At perihelion-->      </PLANET>      <PLANET>          <NAME>Venus</NAME>          <MASS UNITS="(Earth = 1)">.815</MASS>          <DAY UNITS="days">116.75</DAY>          <RADIUS UNITS="miles">3716</RADIUS>          <DENSITY UNITS="(Earth = 1)">.943</DENSITY>          <DISTANCE UNITS="million miles">66.8</DISTANCE><!--At perihelion-->      </PLANET>          .          .          .