Re: [xml-dev] URI Design

["M. David Peterson" <m.david.x2x2x@gmail.com>]

Hey, this is pretty cool.  In my opinion and in answer to your
hierarchical question the time to use a generalogical structure as
part of your XML-based language is if you plan to use these
relationsips as a way of enforcing an implied set of logical
processing rules.  For example, if there is no child element "doThis"
then obviously this method is not available for that portion of your
code base... quick and dirty error checking.  You can also make nested
structure that will step through to each child element until it
evaluates to true (based on whatever you are testing for. e.g. using
the value of the data and the  name() or local-name() of the element
to determine the name of a sequence that should then be invoked to
properly the child elements of the parents name value being tested.  
An example of each of the XML trees for something like this might look
like:

Data being processed:

<foo>
   <bar>
     <element>data</element>
     <element>data</element>
   </bar>
</foo>

Data its being compared against:

<foo true-sequence="seq1">
   <bar true-sequence="seq2"/>
</foo>

Sequence definition file:

<sequence id="seq1">
   <do_this/>
   <then_this/>
   <if_this>
       <do_this/>
   </if_this>
</sequence>

Using this type of dynamic application construction can be really
powerful and as long as you seperate the XML definition files out into
seperate files, allowing only elements and data that are there serving
the same purpose (e.g. to invoke a processing sequence) then I think
you will find this a simple way to maintain decent code readability as
well as the ability to use the structure viewing tools contained
within the tools we use an extremely powerful way to view whats taking
place in your code without having to scan a 2000 line file up and down
looking for this sequence or that sequence, etc...

I really like your chosen style. I would be interested in seeing how
this continues to develop for my own learning so please keep us up to
date, or if you would prefer, just those of us who want to watch by
creating an Atom feed that we can subscribe to.

Cheers :)

On 4/21/05, Alan Gutierrez <alan-xml-dev@engrm.com> wrote:
>     I'm working on my XML pipeline engine, Relay. I'm using special
>     URIs to view information as documents. I'm creating a servlet,
>     for example, that explodes the HttpServletRequest into a
>     document, so I can bite into it with XSLT.
> 
>     <request>
>       <path-info>/foo/bar</path-info>
>       <server-name>engrm.com</server-name>
>       <content-type>application/x-www-form-urlencoded</content-type>
>       <content-uri>request://content/</content-uri>
>     </request>
> 
>     The above document is available from the URI:
> 
>     request://document/
> 
>     As you can see, I get the input as a stream using:
> 
>     request://content/
> 
>     I parse the content of the post in a Relay, and it makes each
>     form field avaialable as a stream, in case one of the fields is
>     really a hidden field with an JavaScript generated XML document in it.
> 
>     Or, else, I can run a textarea through HTML Tidy, to permit mild
>     markup in a comments box.
> 
>     That URI looks like:
> 
>     request://field/e-mail-address/1
> 
>     Which will return the first field named e-mail-address as a
>     stream.
> 
>     What do you all think? Am I designing these URIs correctly?
> 
>     Should I bother making them heirarcical? Or should I simply
>     create my own interpreation of the scheme specific part?
> 
>     request:document
>     request:content
>     request:field:e-mail-address[1]
> 
>     Thanks.
> 
> --
> Alan Gutierrez - alan@engrm.com
>     - http://engrm.com/blogometer/index.html
>     - http://engrm.com/blogometer/rss.2.0.xml
> 
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-- 
<M:D/>

:: M. David Peterson ::
XML & XML Transformations, C#, .NET, and Functional Languages Specialist