Re: Coding aroung a "Cannot convert zero-length string

On 8/13/07, Angela Williams <Angela.Williams@xxxxxxxxxxxxxxxxxx> wrote:
> I've found problems with using the not($stringIsEmpty) construct where I
> get a false true result, I suspect due to the presence of a node-set
> that is empty as opposed to an empty string.

That's probably because you haven't typed your parameters - if you
pass <foo> to a function that expects a string then <foo> gets
converted into a string, which is the same as not(xs:string(foo)).

If you pass <foo> to a function whose parameter is untyped the you
have not(foo) which is false for <foo/>

So basically always type your parameters - if you're expecting a
string that can be empty then you want:

<xsl:param name="foo" as="xs:string?"/>

...and then using test="not($foo)" should be fine.



> I've found if (not(string-length($input-date) eq 0 ) to be much more
> reliable, if more verbose.  I'm using Saxon 8.9 and XSLT 2.0.
>
> Are there other considerations for choosing one solution vs. the other?

Apart from not needing to do it,  Mike Kay has suggested that
string-length is relatively expensive because of the need to sort out
surrogate pairs before counting characters.

cheers
andrew
-- 
http://andrewjwelch.com