XSLT Functions

[daz_oldham]

Hi

I am doing an XSLT that processes (for example) a list of hotels.
Each hotel has the attribute @StarRating which is one of the following
values:

*
**
***
****
*****

Is it possible to pass my attribute to a custom function that could
then do in effect a case statement on them, replacing it with an image
to represent the star rating?

I am sure that it is, but if not, how do you work around this?

Many thanks

Darren

 

[Martin Honnen]

daz_oldham wrote:

Each hotel has the attribute @StarRating which is one of the following
values:

*
**
***
****
*****

Is it possible to pass my attribute to a custom function that could
then do in effect a case statement on them, replacing it with an image
to represent the star rating?

Are you using XSLT 1.0 or 2.0?
Only XSLT 2.0 allows you to write custom functions with XSLT itself.
With XSLT 1.0 you need to write a named template e.g.

<xsl:template name="get-image">
<xslaram name="stars" />
<xsl:variable name="starCount" select="string-length($stars)" />
<img alt="{$starCount} stars"
src="starsImage{$starCount}.gif" />
</xsl:template>

You can then call that template with e.g.
<xsl:call-template name="get-image">
<xsl:with-param name="stars" select="@StarRating" />
</xsl:call-template>

That is simply an example assuming that an HTML
<img alt="4 stars" src="starsImage4.gif">
should be generated for the attribute value '****'.

 

[daz_oldham]

I am using XSLT 1.0 Martin, changing my version to 2.0 in my xslt
didn't seem to make any difference, so I am presuming that with what I
am doing I could fairly easily switch to version 2 and use the
functions.

Or am I being a little naiive there?

Many thanks

Daz

 

[Andy Dingley]

I could fairly easily switch to version 2 and use the functions.

Calling a named template under XSLT is perhaps a little verbose,
compared to other languages, but it's a simple and straightforward
solution that's easily coded and understood by any XSLT coder. I'd
stick with 1.0

 

[Martin Honnen]

I am using XSLT 1.0 Martin, changing my version to 2.0 in my xslt
didn't seem to make any difference, so I am presuming that with what I
am doing I could fairly easily switch to version 2 and use the
functions.

I am not sure what you want to achieve and doing actually, you can use
an XSLT stylesheet with version="1.0" and run that with an XSLT 2.0
processor, you can use a stylesheet with version="2.0" and run that with
an XSLT 1.0 processor, those scenarios are possible but each has its
problems and pecularities. Usually it is best to use an XSLT 1.0
processor to run XSLT 1.0 stylesheet and an XSLT 2.0 processor to run
XSLT 2.0 stylesheets.

The main difference between an XSLT 2.0 function and an XSLT 1.0 named
template is that you can call a function from any XPath expression while
you always need the xsl:call-template instruction to call a named template.

 

[daz_oldham]

Well Martin, Andy - you've both lost me - not that it is something that
is difficult to do

I will continue in 1.0 - I am working in ASP.NET 2.0 for the web, so I
will have no problems there.

As I say, I am looking to do basic lookups on things like "*****" for
hotel star ratings and things like that - nothing too difficult.

Thanks for your help - I really appreciate it as I say to everyone who
pitches in on the newsgroups - its a good community

Daz

 

[Joe Kesselman]

Personally, I'd use the string-length function to get the number of
asterisks, and use that to construct the name of the image. Depending on
how much control you have over the source of the documents, you might
first want to apply an appropriate translate() operation to discard any
whitespace characters.

If you need something more sophisticated, it can probably be done...

 

[daz_oldham]

There is a little bit more to it than this, in that the star ratings
are not actually consistent.

They may come through as 2STARS, 2* and other variations. If I were
doing this in C#, I'd just do a case statement on the string and then
replace it with an image name, and ideally this is what I would have
liked to have done in my XSLT.

Regards

Darren

 

[Andy Dingley]

They may come through as 2STARS, 2* and other variations.

Do you have to deal with "two" and variants? Hopefully not.

What you could do is to take the input and translate it twice. Once to
extract the stars (discard other characters) and take the length, the
other to extract the digits (discard other characters) and evaluate it
as a number. Use the number value if it's >0, otherwise take the
star-count.

 

[Joe Kesselman]

They may come through as 2STARS, 2* and other variations. If I were
doing this in C#, I'd just do a case statement on the string and then
replace it with an image name, and ideally this is what I would have
liked to have done in my XSLT.

If that's what you want, the suggestion elsewhere of a named template
may indeed be the best one. In XSLT 1.0, named templates can't be called
as functions... but their results can be assigned to variables so you
can do most of the same things with them, albeit a bit more verbosely.

 

[daz_oldham]

I think this may be the way to go for me on this one Joe.

I am starting to wonder if indeed XSLT is the way to go on this, and
maybe I should parse the XML with XMLDOM in my ASPx pages.

Many thanks for your input.

Darren