i do agree that functional aspects of XSLT are
important. in fact, i was enlightened by Dimitre's
article at http://fxsl.sourceforge.net , where he
explained how XSLT can be equated with a functional
programming paradigm.. as Dimitre has explained , if
we imagine the XSLT templates as functions and treat
functions as higher-order we can produce very
effective techniques in the context of handling XML ..

if *only* variable increment is allowed in XSLT , to
how much extend would it introduce side effect can be
debated .. i guess, variale scoping will be a big
problem if variables are allowed to increment ..

i guess XSLT was invented to solve XML transformation
problem .. since XML is like a tree structure , so a
language to transform XML should be recursive and
functional ..! if somebody wants a imperative
programming style to handle XML , they can use DOM! 

Regards,
Mukul


--- Wendell Piez <wapiez@xxxxxxxxxxxxxxxx> wrote:
> Mukul,
> 
> I'm also curious as to why this restriction is
> imposed on XSLT, and never 
> fail to listen with interest to cogent explanations
> of the theory behind 
> functional, "side-effect-free" programming.
> 
> However, otherwise I disagree. I like XSLT's
> functional aspects, and am 
> greatly relieved not to have to pay attention to the
> kinds of things that 
> more procedural languages burden the programmer
> with. In other words, I do 
> not believe that this design decision represents a
> net loss, or that XSLT 
> would be "really easy" if it allowed more side
> effects: on the contrary, 
> I'm thankful that I can only imagine what XSLT would
> be like if it were 
> more procedural.
> 
> After all, if you like that kind of programming
> there are plenty of tools 
> available. People used to write markup transforms in
> Perl, and it's still 
> very useful if you know what you're doing.
> 
> I think experience on this list also shows that many
> times, neither an 
> incrementable variable nor recursion is really
> necessary. (And note that on 
> the list we see the hard cases, and never hear about
> all the things that 
> are easy.) Just as often, when the "problem" of
> variable scoping comes up, 
> a programmer who is not familiar with the XSLT
> processing model is jumping 
> to conclusions about how something needs to be done.
> XSLT lets the 
> programmer concentrate on the "what", leaving most
> details of "how" to the 
> engine. For whatever reason, some programmers don't
> understand this or 
> don't like it, and insist on thinking too hard.
> (Admittedly there's a 
> blurry line there. But note also that recursion and
> such sophisticated 
> techniques come up on the list more often to handle
> problems that XSLT 
> wasn't designed to deal with, like string munging,
> than they do just to get 
> around the restrictions on variables.)
> 
> Just $0.02 from me. Interesting question.
> 
> Cheers,
> Wendell
> 
> At 12:10 PM 6/27/2003, Mukul wrote:
> >   We all know that XSLT does not allow
> incrementing a
> >variable after declaring it. Myself and many of us
> >fell that it a major handicap in writing programs
> >easily in XSLT. To simulate the variables we have
> to
> >use recursion and many sophisticated techniques. If
> >there is a feature of full scale variables in XSLT,
> it
> >would make programming really easy. I am curious
> why
> >this restriction is imposed in XSLT specification.
> 
> 
>
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> Wendell Piez                           
> mailto:wapiez@xxxxxxxxxxxxxxxx
> Mulberry Technologies, Inc.               
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