XSLT: a simple question

ratnalein · February 4th, 2013, 09:39 AM

Hallo everyone,

I have this code line:

Code:

...
...
<xsl:value-of select="tag/childTag"/><xsl:text>"</xsl:text>
...
...

I would like to ask, what would happen, if in my xml file there is no element called tag or childTag? Would the processor just ignore the code line or will it output an error?

Another question:
I always thought that I have understood XSLT, but I am confused regarding these 2 terms:
1. XSL file
2. XSLT Style Sheet

Are they the same? Is a XSL file always a XSLT Style Sheet? Thank you for your help.

Regards,

Ratna

mhkay · February 4th, 2013, 10:47 AM

If there is no child element matching tag, or grandchild matching childTag, then the select expression selects an empty sequence, the xsl:value-of instruction converts this result to an empty string, so the effect is to output an empty string, which in practice means the instruction does nothing.

The term "XSL" is best avoided, because different people use it to mean different things. Sometimes people use it as a synonym for XSLT, but not always; sometimes they mean XSL-FO, for example, and in Microsoft at one time it meant the Microsoft dialect of XSLT called WD-xsl.

ratnalein · February 4th, 2013, 12:24 PM

Hallo Michael,

thanks for the help.

continuing the question regarding "what would it be, if...":

Code:

<xsl:for-each select="Tag"> 
       <xsl:value-of select="'1~'"/>
       <xsl:value-of select="Tag_1/Tag_1_1"/><xsl:text>"</xsl:text>     	
       <xsl:value-of select="Tag_2"/><xsl:text>"</xsl:text>
</xsl:for-each>

In the XML file, there is no tag "Tag", so for-each can not be processed. BUT, there are "Tag_1/Tag_1_1" and "Tag_2".
Will my Saxon Processor still output the value from "Tag_1_1" and "Tag_2"?

Last question:
What is the meaning of <xsl:value-of select="'1~'"/> ? Is it a constant?

Thank you for the help.

Regards,

Ratna

mhkay · February 4th, 2013, 12:26 PM

If select="Tag" selects nothing, you are iterating over an empty sequence, so the body of the loop is executed zero times.

<xsl:value-of select="'1~'"/> outputs the string literal "1~" (it's easy enough to try it and see!)