We’ve become familiar with an approach to customization that emphasizes the modules and the individual elements, and you’ve all had practice in constraining your data in this way—in deleting entire modules, based on whether you need the elements that have to do with a specific genre or type of markup, and in deleting individual elements, based on whether you want to use a specific element or not.
Now we’re going to take a look at another way of approaching constraint: by deleting classes of elements, based on whether you need the elements that perform a certain kind of function in the text, or occupy a certain kind of space within the text.
Let’s come back to the slide we saw earlier, showing how model classes represent functional groupings of elements.
What if we didn’t want to represent any kind of milestones in our document—no page breaks, no column breaks, no line breaks, no page numbers or other kinds of forme work, no anchors? These elements come from three different modules, one of which is the core module, so we can’t delete them all just by excluding a module. If we want to delete them as a group and make it easy to represent that deletion as a single functional decision, we need to delete the model class that contains them.
