RE: A sequence of more than one item is not allowed as

> In summary then, when building a string in a variable and you want to
> avoid document node creation it's preferable to use item()+ than
> xs:string+ as that allows the merging of adjacent text nodes before
> atomization, creating a sequence of one item therefore bypassing the
> separator issue?

No, if you want to build a string in a variable then you should define the
type of the variable as xs:string.

You can either do:
> 
  <xsl:variable name="foo" as="xs:string">
   <xsl:value-of>
    <xsl:text>abc</xsl:text><xsl:value-of select="'def'"/>
   </xsl:value-of>
  </xsl:variable>

or

  <xsl:variable name="foo" as="xs:string">
   <xsl:sequence select="concat('abc', 'def')"/>
  </xsl:variable>

or of course

  <xsl:variable name="foo" select="concat('abc', 'def')"/>

Personally I prefer to work entirely with strings. If you don't need text
nodes, don't create them.

Michael Kay
http://www.saxonica.com/


> 
> <xsl:template match="/">
>   <xsl:value-of select="$foo"/>
> </xsl:template>
> 
> Gives the required 'abcdef'
> 
> <xsl:variable name="foo" as="xs:string+">
>   <xsl:text>abc</xsl:text><xsl:value-of select="'def'"/>
> </xsl:variable>
> 
> <xsl:template match="/">
>   <xsl:value-of select="$foo"/>
> </xsl:template>
> 
> Gives the unwanted 'abc def'
> 
> Hmmmmmmm...