Elements with explicit behavior versus elements that contain dataused to

[Roger L Costello <costello@mitre.org>]

Hi Folks,

Consider this XML element:

<xsl:value-of select="/BookStore/Book[1]/Title"/>

That is an element (value-of) and the element has an attribute (select). That element means something. It has a specific behavior. Namely, it returns the value of the element identified by the XPath expression (/BookStore/Book[1]/Title). Conceivably there could be a computer whose hardware directly operates on this XML element.

Next, consider this XML element:

<airport>
    <name>Logan Airport</name>
    <instrument-departure>
        ...
    </instrument-departure>
</airport>

That element (airport) does not have a behavior. But the data in that element is ingested into an aircraft's flight management system (FMS) and then used to fly an aircraft out of the airport. 

In the first case the element has explicitly defined behavior whereas in the second case the element has data that is ingested by an application to produce a behavior. 

The distinction is somewhat subtle, but important I think.

I would like to hear your thoughts on this. Is the distinction useful?

/Roger