[uf-dev] Defining and Extending Value Excepting

Ben Ward lists at ben-ward.co.uk
Sat May 17 11:47:01 PDT 2008

Hi parser devs!

I've spent a number of hours this weekend documenting cases of  
microformats requiring particular data formats for parsing (ISO 8601,  
telephone keywords in hCard, and so on).

Alongside this, I've documented the current supported means of  
including said data (class-design-pattern, abbr-design-pattern and  
value-excerpting), noting how the intention of authors is to hide  
these specified formats in favour of more flexible human-centric  
formats. Alongside that, I've documented where different means of  
inclusion are appropriate and inappropriate in different situations.

Finally, I've proposed an extension to the current pattern of value- 
excepting, whereby cases where an element with a class of ‘value’ is  
also empty, it would have the @title attribute parsed in place of  

I am aware that we need to better specify the behaviour of value- 
excerpting as a whole, let alone adding extensions. We do, however,  
have a problem that can be solved; the requirement is to include  
specific data formats, but hidden in place of variable, human  
consumable forms of that data (or internationalised), whilst still  
operating entirely within the HTML layer (not depending on CSS). This  
is not something that HTML has a native means of handling.

The way I see it, at the same time as properly specifying value- 
excerpting (possibly just calling ‘value-design-pattern’), we can  
specify a robust means of handling the exceptional requirement to  
include machine data.

** What I'd like from parser developers is feedback on how feasible  
this pattern is to parse, please. **

Note that whilst this proposal _does_ resolve the long running abbr- 
misuse issue that keeps coming up, my approach here is in solving the  
root of the problem, not of working around a consequence of that  
problem. Additionally, in extending the existing value-excerpting  
behaviour, we avoid adding yet more syntactic vocabulary to  
microformats and we produce a pattern that does not tie people to  
particular HTML elements (which is more inline with our microformat  

With regard to the separate issues we've had with ABBR, I'm asking  
some colleagues to test this idea thoroughly with regard to assistive  
technology before we finalise a spec.



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