Proposal for 'expanded' attribute in OPML 2.0

Friday, August 31, 2007 by Dave Winer.

After discussing the idea of an expanded attribute for outline elements, I got a key new piece of information -- in some applications there is no distinction between a file format and an application's internal data structure. An example are Javascript apps running in a web browser. For them, my advice that expansionState not be maintained while the app is running is impractical.  

I asked if there were apps ready to take advantage of this, and while no clear answer came back, I believe that if OPML had the ability to express expansion state as an outline-level attribute, such apps might appear in relatively short order. Therefore I'd like to offer a proposal and hear what people think. 

Proposal: Add a paragraph to the Other special attributes section of the OPML 2.0 draft spec:

"expanded is a string with two possible values, true or false. If true, the outline element is said to be expanded, its first-level sub-outlines are visible when displayed. Its optional. If the attribute is not present, the outline's first-level sub-outlines are not visible when displayed."