Re: [xsl] Basics of XSLT

[Nic Gibson <nicg@xxxxxxxxxx>]

2009/3/10 himanshu padmanabhi <himanshu.padmanabhi@xxxxxxxxx>:
> Thank you.Can anyone explain XPath more?
>
> I was advised to use "XML::LibXSLT::xpath_to_string" in the following code.
>
> B my $parser = XML::LibXML->new();
> B my $xslt = XML::LibXSLT->new();
>
> B my $source = $parser->parse_file($xmlfile);
> B my $style_doc = $parser->parse_file($xslfile);
>
> B my $stylesheet = $xslt->parse_stylesheet($style_doc);
>
> B my $results = $stylesheet->transform($source,
> XML::LibXSLT::xpath_to_string(args => "$in{'args'}",value => "$value",
> cnt => "1",);
>
> B print $stylesheet->output_string($results);
>

Hello again.

One thing you might find useful is the perl-xml mailing list (take a
look at http://aspn.activestate.com/ASPN/Mail/Browse/Threaded/perl-xml).

I'll try and answer your question about xpath_to_string. In xslt the
value of a parameter (or variable) is an xpath exrpession in something
like:

<xsl:param name='myparam' select='foo'/>

That is, we aren't talking about the string 'foo' here, we are talking
about the element 'foo'. Now, that is like to not be what you mean in
a global parameter (one at stylesheet level as opposed to a local
param at template level). A string must be quoted in an xpath
expression:

<xsl:param name='myparam' select="'foo'"/> <!-- double quote with
single quoted string inside it -->

So... going back to perl - xpath_to_string converts a perl string to
the quoting format required by xslt.

The input to the function is a hash (or an array of key/value pairs).
Basically the function takes every second argument and quotes it. It
then returns the processed array. So, the result of:

XML::LibXSLT::xpath_to_string(args => "$in{'args'}",value => "$value",
 cnt => "1",)

will be

('args' => "'xxx'", 'value' => "'yyy'", 'cnt', => "'1'"); # double
quoted strings containing single quoted values

where xxx and yyy are the values of $in{'args'} and $value respectively.

I think I gave you an incorrect answer yesterday because I suggested
xpath_to_string('foo') - don't do that, do as you were doing before
(xpath_to_string('foo', 'bar')).


cheers

nic

--
Nic Gibson
Director, Corbas Consulting
Editorial and Technical Consultancy
http://www.corbas.co.uk/