Re: [xsl] generating ID strings that are both readable and unique

[Xmlizer <xmlizer+xsllist@xxxxxxxxx>]

Dear,

Give a try to use generate-id(), perhaps by using it with concat()

Xmlizer

On Tue, Oct 14, 2008 at 8:25 AM, Trevor Nicholls
<trevor@xxxxxxxxxxxxxxxxxx> wrote:
> Hi
>
> In this particular application we have a set of XML documents which are
> divided into nested sections; each section may (down the track) give rise to
> a url. Currently that url is generated by <xsl:number level="multiple"> but
> this produces urls that change frequently. Some sections have been given an
> ID attribute by the process which originally created the documents, but most
> have not.
> Additionally, all sections must have exactly one title child, along with
> their other content.
>
> The requirement is to process an XML file and generate an ID attribute for
> sections which lack them - deriving the ID value from the title so that the
> url is comprehensible. Providing we ignore the problem cases, this is a
> trivial exercise:
>
> ----
>
>  <xsl:variable name="upchars" select="'ABCDEFGHIJKLMNOPQRSTUVWXYZ'" />
>  <xsl:variable name="lochars" select="'abcdefghijklmnopqrstuvwxyz'" />
>
>  <!-- catchall -->
>  <xsl:template match="*">
>   <xsl:copy>
>     <xsl:apply-templates select="@*" />
>     <xsl:apply-templates />
>   </xsl:copy>
>  </xsl:template>
>
>  <xsl:template match="@*">
>   <xsl:copy-of select="." />
>  </xsl:template>
>
>  <xsl:template match="section[@id]">
>   <xsl:copy>
>     <xsl:apply-templates select="@*" />
>     <xsl:apply-templates />
>   </xsl:copy>
>  </xsl:template>
>
>  <xsl:template match="section">
>   <xsl:copy>
>     <xsl:attribute name="id">
>       <xsl:apply-templates select="title" mode="id" />
>     </xsl:attribute>
>     <xsl:apply-templates select="@*" />
>     <xsl:apply-templates />
>   </xsl:copy>
>  </xsl:template>
>
>  <xsl:template match="title" mode="id">
>   <xsl:value-of select="translate(translate(.,' ','_'),$upchars,$lochars)"
> />
>  </xsl:template>
>
> ----
>
> The problem cases are
> (a) duplicate titles (after the translations) which would lead to duplicate
> IDs, and
> (b) existing IDs which might also duplicate a title.
>
> If there were no IDs in the document to begin with, I think I could have
> solved the first problem by using a key. But the second problem complicates
> it, and I haven't got enough experience with keys to figure out how to
> adjust the "id" mode title template to take both issues into account.
>
> Can anyone offer some helpful advice here?
> XSL 1.0 is preferred, although I would be interested to see how XSL2 might
> handle this problem too.
>
> Thanks
> Trevor