Re: EARL structure and processing model

At 17.48 07/04/2005, Carlos A Velasco wrote:
>I believe that EARL shall be flexible enough to allow different Location 
>approaches depending on the resource's type. I don't have any brilliant 
>solution at the moment, but it is something we must include in the 
>requirements. We shall not simply disregard these resources, and then say 
>"for that resource, we give only its URL as location of a problem."

Exactly. We briefly discussed this - I guess - in the call immediately 
after Easter.

Well, this is a difficult concept for me to explain, but I will try. So 
please bear with me. :-)

IMO location should be depending on the resource type. Better, on the 
specific algorithm used to locate/retrieve subjects regarding a particular 

For instance, for XHTML and HTML you can use fuzzy pointers based on 
xpath-like expressions and other properties that can help locating a 
subject, for CSS you can use another kind of pointers based on CSS 
properties, on text files (and programming languages) you can use line numbers.

As you can see, every resource type has its own locating mechanisms which 
produce (output operation) and use (input operation) different expressions 
and different approach to refer to a particular fragment of a resource.

Binary files will have different ways of referring to a particular subset 
of the whole file. PDF locating mechanisms will be different from JPEG 
images or AVI files, etc. Each type will have its own locating mechanism.

And EARL should be flexible in order to allow these way of acting.

It's getting harder for me to explain. However, see it in an Object 
Oriented way: every resource type will specifically (or polymorphically) 
redefine the behaviour of these mechanisms and use properties that can vary 
from type to type.

In a very skimmed and sketched way, here is this example in my mind:

|-- Text files Location
     |-- HTML Location
     |-- XHTML Location
     |-- Plain text Location
     |-- CSS Location
     |-- C Source file
     |-- etc.
|-- Binary files Location
     |-- PDF Location
     |-- JPEG Location
     |-- and so on ...

Any comments?

Gabriele Bartolini: Web Programmer, ht://Dig & IWA/HWG Member, ht://Check 
and ht://Miner maintainer
Current Location: Prato, Toscana, Italia | | ICQ#129221447
 > "Lasciate ogne speranza, voi ch'intrate", Dante Alighieri, Divina 
Commedia, Inferno

Received on Thursday, 7 April 2005 19:52:58 UTC