Re: [xsl] Converting a string to Uppercase or Lowercase without using t

> I suppose ... I guess I see the problem as a lexical issue and not an 
> algorithmic issue.  I cannot comment on optimization opportunities 
> for XSLT engines when faced with an explicit string or a variable 
> reference ... perhaps someone on the list can comment on this.
Without looking at what any real system does I'd expect the variable to
be more efficient (in general) Although I doubt it's measurabl:-)
with an entity ref you first have to expand all the entities 
and then the XSLT engine has to parse  each instance as a new string
literal, whereas with a variable reference the string is internalised
just once as an xpath string and then accessed by reference (unless the
optimiser decides to inline the variable reference I suppose...)

> Would you tackle the following with a variable as well?
>
> <!DOCTYPE xsl:stylesheet [
>     <!ENTITY nbsp '&#xa0;'>
Personally I've never seen the facination with "nbsp" "#160" seems to be
just as good a spelling of that character name, so I'd just use &#160;

> I don't think people new to XSLT should forget that we are, after 
> all, working with XML files.
Although one problem with using entities like this is that some XML
parsers forget that a <!DOCTYPE reference doesn't imply a request to
validate so can generate lots of spurious warnings that the stylesheet
is invalid.

One use I have seen for entities in XSLT1 is as a proxy for function
definitions. Rather than having entities for xpath literals as in teh
examples here you can have an entity that expands to a boolean predicate
which you use as foo[&bar;] with teh predicate being evaluated each
time. Again though in xslt2 you can just parse the predicate once by
making it a function accessed like foo[my:bar(.)] which is often nicer
than using entity expansion.



David

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