theories of media languages and error handling

[Bryan Rasmussen <bry@itnisk.com>]

There is an assumption one often encounters in implementations for media (as a
reference media I will focus on hypermedia in the modern browser), this
assumption is opposition to a general assumption for validation of data for
media, the media implementation assumption could be put as follows:

 The absence of an object does not cause the failure of the whole. This means
that as a general rule if I refer to some object that the browser cannot find
the browser is not designed to fail, the browser assumes that other objects
that
it can find are still useful to the user and do not present a faulty instance
to
the user (sometimes of course the browser does fail but such failures at
missing
components seem always to be due to bugs in the browser and not required
presence)

As an example of this assumption -  a reference to an image that the browser
cannot resolve, this is generally the same behavior in printing etc.


I am in total aggreement with this assumption. 

The assumption for validation of data for media is often as follows:

strict requirements for structure prevents failures in your media presentation.
But of course that someone has put in an element referring to an image does not
mean the image is placed in the page. 



In a way we can define the components of a media instance as being loosely
coupled. How though has it come to pass that this is so? Is there any theory out
there or do people have theories? I suppose the pedestrian reason is that media
itself is dataless and any media format must allow decoupling of individual
media elements because we cannot know what their meaning is without the data
context. so that if one had a true xml browser that was semantically aware we
would be able to crash whenever a document without a required image was
enquired. 

I am of course aware of the oodles of theory on strict validation of document
structures and so forth and why failure when data standards are not held to is
good. I am however sometimes worried that this kind of strictness is only proper
in some very few instances.  



 






-- 
Bryan Rasmussen