Subject: Re: [xsl] What's your visual metaphor for XSL Transformations? From: "Dimitre Novatchev" <dnovatchev@xxxxxxxxx> Date: Wed, 21 Mar 2007 20:12:39 -0700 |
I used to write a lot of recursive functions in C , but have now forgotten all about recursion since I didn't use it since school.
I plan to read this: http://en.wikipedia.org/wiki/Recursion carefully to remember it again, I think it is useful to know especially in XSLT.
One will not wonder what recursion is if they are in good terms with proof by induction.
Both need to have some empirical base (some N0, N1, ... etc.) for which F(N) is true,
then we assume that F(k) is true and based on this prove (calculate) that F(k1) is true, where k1 > k (typycally k1 = k + 1, but we may use k1 = 2*k, or any other convenient relation)
Then comes the big plunge down to the base of induction/recursion -- and here's where we use the base of the proof/calculation. F(base) is true and we have proved that from F(N) it follows F(k(N)),
that is, we have proved/calculated F() for any argument of the form k(k(...k(base))...)
Therefore rather than a dragon trying to eat his tail, my visual metaphore for recursion would be one or several Vienese wheels, some going up and some going down, but all of them stopping at initial moments to pick passengers (base).
To put it simply, something with a definite start that can go on for as long as one needs to.
Often a proof by induction is carried over on an infinite set of arguments (such as all natural numbers) and the same may be possible to accomplish with recursive processing with indefinite depth, where the argument is an infinite list of items and the processing and producing of results is carried out in "real time", "streaming" mode.
Probably fractals would be a better visual metaphore for such kind of recursive processing.
-- Cheers, Dimitre Novatchev --------------------------------------- Truly great madness cannot be achieved without significant intelligence. --------------------------------------- To invent, you need a good imagination and a pile of junk ------------------------------------- You've achieved success in your field when you don't know whether what you're doing is work or play
Nice post.
It would be interesting to know how a recursive template could be visualized.
A few days ago I posted a request on this list to create an HTML menu in the form of ul , li tags recursively. I found it tough to visualize the answer that was posted.
I used to write a lot of recursive functions in C , but have now forgotten all about recursion since I didn't use it since school.
I plan to read this: http://en.wikipedia.org/wiki/Recursion carefully to remember it again, I think it is useful to know especially in XSLT.
-Rashmi
> On 3/21/07, W Charlton < XSLList@xxxxxxxxxx> wrote: > > > > When working with an element or attribute I have a mental awareness of where > > I am in the "branch" with relation to the other "branches" that I am trying > > to access or manipulate.
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