Re: [xsl] top level xsl:param confusion

[Robert Koberg <rob@xxxxxxxxxx>]

Hi,

Wendell Piez wrote:

> Robert,
>
> At 06:09 PM 9/30/2004, you wrote:
>
> > Hi and thanks,
> >
> > I was hoping to get the benefit of a quick boolean test. Perhaps this 
> > is a JAXP thing? I would think setting a parameter to an empty string:
> >
> > transformer.setParameter("permission", "");
> >
> > would equate to (if the permission param was not sent):
> >
> > <xsl:param name="permission" select="''"/>
> > (since that is what I am passing)
>
>
> Yes, but if you then test="$permission", the test will fail, because the 
> empty string tests as false. (This is what David and others have tried 
> to tell you.)

I got that after after a few other posts (especially Wolgang's and 
Bertoni's).

fact of life...

> Setting the parameter to default to "false()" is not the same as setting 
> it to have no value: it has a value, precisely, of Boolean false. 

Yes, I get that. If the parameter is not sent to the transformation then 
I want it to be false(). My thinking was that:

<xsl:if test="$myBool">

</

is more performant than:

<xsl:if test="not($myStr='')">

</


> When 
> an empty string is coerced to a Boolean, as it always is when it is 
> tested directly, it also gets a value of false.

I realize it is in the spec (now...) and I have to live with it. I guess 
I was thinking along the lines that:

'' != false()

in any other languages I have dealt with,

Also, it appears to be inconsistent (I understand a @test is not a 
@select, ) that:

<xsl:value-of select="''"/>

does not output false. So if it can be selected and output then why 
should it evaluate to false?

just rambling... :)

> > To me, this seems like a bug for java processors (at least Saxon and 
> > Xalan)
>
>
> No, it's the way the spec outlines the built-in casting of datatypes.
>
> If it were my project, I'd set the default to the string ".", which 
> would not test as false, and which conveniently means, in most 
> directory-traversal syntaxes, the current working directory.

That is what I did :) (actually './')

thanks,
-Rob


> Cheers,
> Wendell
>
>
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