Re: Basic program structures in XSLT (was: Re: [xml-dev] Data-driven application --> the data is essentially "machine code" to the application, right?)

On Fri, Dec 9, 2022 at 3:46 PM G. Ken Holman <[email protected]>
wrote:

> At 2022-12-08 10:52 -0700, C. M. Sperberg-McQueen wrote:
> >are there analogous basic
> >principles for program design which can be used to guide construction of
> >a transformation in XSLT?
>
> The focus/orientation of program design from the programmer's
> perspective is the document order of the output, which is totally
> independent of the document order of the input.
>

JLK: This is the most succinct description I've seen in this conversation,
although others have mentioned it in addition to other concepts. XSLT
enables rearranging content for context-specific purposes without
rearranging the source.


> (though being the same helps)
>
> (many students would ask me about "going back" and "fixing" or
> "adding to" content that already has been processed)
>
> That and the already mentioned distinction of push and pull comprise
> most of the introduction lecture in my XSLT class.
>
> JLK - I've seen this described elsewhere as the difference between
imperative and declarative. A long time ago, in an Arbortext far away, we
talked about "Declarative vs. Procedural." Ian Williams boiled that down to
a sentence: "an XSLT programmer does not define a sequence of actions, but
specifies a number of rules that. the result should satisfy."

(I think a lot about this stuff these days. I have direct reports in India
who are still learning. I need to find the easiest way to state stuff that
often gets stated in any number of ways [see note about Arbortext above]
over time.)