Re: [xsl] Defensive programming in XSLT using asserts and as="..."

["Liam R. E. Quin liam@xxxxxxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

On Fri, 2022-05-06 at 16:27 +0000, Michael Kay mike@xxxxxxxxxxxx wrote:
> If you can express the condition with an @as attribute, use that in
> preference to an xsl:assert, because it's much more amenable to
> static analysisB 

This is a good reason; another is that programming errors in assert
expressions are much less likely to be caught than mistakes in as=

For example,
> >
> > <xsl:param name="item" as="element(author)"/>
> >
> > is equivalent to:
> >
> > <xsl:param name="item"/>
> > <xsl:assert test="name($item) eq 'author'"/>

except of course, as Mike Kay pointed out, it isn't - not only for the
reasons he gave, but also because when you use as="element(author)",
every single use of that parameter will be tested automatically, so
<xsl:sequence select="$item + 6" />
can raise a static error.


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Available for XML/Document/Information Architecture/XSLT/
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