value-class-pattern: Difference between revisions

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(→‎Parsing To-Do: Moving ToDo in separate -issues page)
(Added parsing rules in response to closed value-nesting-in-value issue.)
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==Parsing==
==Parsing==
Parsing rules need defining fully. As a starting point, it works roughly like this.


* Where an element with a microformat property class name has an descendant with class name <code>value</code>, parsers should read the inner-text of the ''<code>value</code>'' element only, ignoring other text node descendants.
* Where an element with a microformat property class name has an descendant with class name <code>value</code>, parsers should read the inner-text of the ''<code>value</code>'' element only, ignoring other text node descendants.
* Where multiple descendants have a class name of <code>value</code>, they should be concatenated.  
* Where multiple descendants of a property all have a class name of <code>value</code>, they should be concatenated, separated by a single piece of white-space (unicode 0020).
 
* Where an element <code>foo</code> with class <code>value</code> has a <em>descendant</em> <code>bar</code> with class <code>value</code>, the entire content of <strong><code>foo</code></strong> is taken as the <code>value</code>. Nesting additional elements with class of <code>value</code> cannot be used to further isolate the value.
Knowledge of other microformats must not be a prerequisite of parsing a microformat using the value-excerption-pattern.
 
 


==Related Pages==
==Related Pages==

Revision as of 18:05, 6 June 2008

Value Excerption Pattern

The value excerption pattern is derived from value-excerpting in hCard. As such, it is already somewhat supported in parsers. However, the precise parsing behaviour is not yet finalised, so the pattern should be used only with extreme caution, and with the awareness that the editing of more precise parsing rules could impact your pages.

Sometimes, only a part of an element's content is used as the value of a microformat property. This may occur when a property has optional sub-properties, such as tel in hCard. Other times, the most logical, semantic element for the property class name may include other content.

For these purposes, the special class name value is used to excerpt out the relevant element content.

Simple Examples

Here is an hCard fragment for marking up a home phone number:

vCard:

<code>TEL;TYPE=HOME:+1.415.555.1212</code>

hCard:

<span class="tel">
  <span class="type">Home</span>:
  <span class="value">+1.415.555.1212</span>
</span>

In this case, the value of tel is +1.415.555.1212, not Home: +1.415.555.1212.

Another example, this time using price in hListing:

<span class="price">
   I want to sell for
   <span class="value">£15</span>
</span>

In this case, price will parse as £15, rather than as the entire sentence.

Another example, using dtstart in hCalendar:

<span class="dtstart">
   Friday 25th May, 6pm
   <span class="value">2008-05-25T18:00:00+0100</span>
</span>

Whilst the entire string ‘Friday 25th May […]’ is semantically the date, it's the ISO 8601 encoded form alone which must be consumed by a microformats parser, so the value class isolates it.

Parsing

  • Where an element with a microformat property class name has an descendant with class name value, parsers should read the inner-text of the value element only, ignoring other text node descendants.
  • Where multiple descendants of a property all have a class name of value, they should be concatenated, separated by a single piece of white-space (unicode 0020).
  • Where an element foo with class value has a descendant bar with class value, the entire content of foo is taken as the value. Nesting additional elements with class of value cannot be used to further isolate the value.

Related Pages