is it possible to use "attribute value templates" in variable or param?

Question

this is nice and short:

<img src="{$base}/{@filename}.jpg" />

but sometimes you need to reuse the src, so it turns into this:

<xsl:variable name="imgsrc">
    <xsl:value-of select="$base">/<xsl:value-of select="@filename">
    <xsl:text>.jpg</xsl:text>
</xsl:variable>
<img src="$imgsrc" />

According to http://www.w3.org/TR/xslt#dt-attribute-value-template you can't use the "curly brackets interpolation syntax" outside of literal element attributes, but there might be a not-so-hacky hack to do the trick? I'm lazy, I know.

Answer 1

You can use a select expression to define the variable, using the concat function to join the various bits together:

<xsl:variable name="imgsrc" select="concat($base, '/', @filename, '.jpg')"/>
<img src="{$imgsrc}" />

This is also more efficient than the <xsl:value-of> approach because by using select you're setting the variable to a string value directly rather than creating a tree fragment containing a text node which then has to be converted back into a string when you reference the variable.

Answer 2

XSLT 3.0 contains some goodies in this area:

(a) a concat operator

select="$base || '/' || @filename || '.jpg'

(b) "text value templates"

<xsl:variable name="x">{$base}/{@filename}/.jpg</xsl:variable>

(which needs to be enabled, for compatibility reasons)