Re: [xsl] What is the relationship between transforming, mapping, and filtering?

["Wendell Piez wapiez@xxxxxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Hi,

Not being a mathematician I can only report (as a philologist) as I
understand it, the mathematicians by 'mapping' mean that a point in
coordinate space A can be identified with a point in coordinate space B.
(Hence B can be used as a 'map' to find your way around A even when the
terrain of A has three dimensions while B has only two.) That would seem to
imply (to me) a one-to-one or many-to-one relation, and (in the context of
document transformation) the preservation of "document order" -- 'renaming'
in the general case, being a case of mapping. (One can also map using
functions, which is different from the renaming case, as intensional vs
extensional. Retaining order.)

When used in a plain 'push' mode, XSLT executes a partial or complete
mapping because it introduces new nodes that correspond to the old nodes
one to one (though this of course is controllable), while regarding the
given order as a default ordering to be respected. (This is key.) This
makes XSLT a natural fit for mapping problems in transformation. Because we
have template matching we need neither type-or name-based case switching,
nor even inline conditionals (when you think about it), since we already
have both.

FWIW either a transformation (actual stylesheet) or its abstract
specification might present a mapping. Maybe they even align.

Filters don't have to be specified or implemented as mappings, although
they might be.

I am not sure what I would call a transformation that does not perform any
mapping as such. Maybe a 'query'. (Although complex queries might do some
mapping.)

These terms are very loose of course and much depends on context. Knowing
what needs to be 'mapped' or 'filtered' is half the game.

Cheers, Wendell



On Tue, Aug 31, 2021 at 2:56 PM Alan Painter alan.painter@xxxxxxxxx <
xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:

> This punter's US$.02:
>
> Transformation: the generic term for the overall process.
>
> Mapping: the creation of output that corresponds directly to some input on
> a fine-grained level.
>
> Filtering: choosing what information to map (or not).
>
> Enriching: adding additional information to that output that does not have
> the input as origin, perhaps from a separate data source or some
> business/logical rules, possibly constructed by the mapping process itself.
>
>
>
> On Tue, Aug 31, 2021, 19:58 Roger L Costello costello@xxxxxxxxx <
> xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
>> Hi Folks,
>>
>> How do you define those terms? Are they synonymous? Is one a subset of
>> another?
>>
>> By "mapping" I mean populating XML instances of one data standard with
>> data from another data standard. For example, I am currently mapping a
>> military air navigation data standard to a civilian air navigation data
>> standard.
>>
>> By "filtering" I mean performing actions on data such as redacting,
>> fuzzing, and zeroing. One could think of these actions as mapping: if I
>> fuzz a lat/long location, I am essentially mapping the location to another
>> location.
>>
>> By "transforming" I mean all the kinds of things you can do with XSLT.
>>
>> Is filtering a subset of mapping? Is mapping a subset of transforming?
>>
>> /Roger
>>
>>
>> XSL-List info and archive <http://www.mulberrytech.com/xsl/xsl-list>
> EasyUnsubscribe <http://lists.mulberrytech.com/unsub/xsl-list/174322> (by
> email <>)
>


-- 
...Wendell Piez... ...wendell -at- nist -dot- gov...
...wendellpiez.com... ...pellucidliterature.org... ...pausepress.org...
...github.com/wendellpiez... ...gitlab.coko.foundation/wendell...