Include and exclude filtering actions

In typical publishing tools, filtering and flagging actions to be taken during processing are defined in a ditaval file.

The DITA values (ditaval) file is used to specify publishing conditions used for processing DITA source into a reading format. The condition actions are specified in the action attribute of the prop element in the ditaval file. Valid action are:
exclude from the output any elements with the specified metadata attributes
highlight, with a text colour, background colour, or image, any elements with the specified metadata attributes
ignore the attribute, but leave the attribute in place in the output
include from the output any elements with the specified metadata attributes
An example of a snippet of ditaval code to flag elements with a product attribute of impress with a small image at the start of the element is:
<prop att="product" val="impress" action="flag">
  <startflag imageref="delta_olive.gif">
    <alt-text>Start of product - Impress</alt-text>

Despite there being an include action in the ditaval logic, there is no purpose for this action. By default, all content is included. Even within a nested set of elements, a higher level element marked as include will have no affect even if lower level elements are marked with exclude. By default, no content is flagged.

Attributes are used to mark elements that are specific or individual to a particular product, platform, audience or other requirement. You only mark up those elements that you want the ability to exclude or flag.

If you are using multiple conditions (that is, more than one value in the same attribute, such as audience="admin manager"), only if all exclude conditions are satisfied will the element will be excluded from the output. In other words, all exclude conditions have to be satisfied for the element to be excluded from the output. So if a paragraph was marked with values of admin and manager, and the ditaval specified that admin should be excluded, but manager included, the paragraph would be included.

Note: You can change this default inclusive behaviour of the ditaval to exclusive by setting the following property as the first node under the val element in the ditaval file:
<prop action="exclude" />