Printed books allow the reader to skim the text and quickly locate portions of interest. Experienced readers use several different techniques to achieve this. One of these is to locate an equation or table and then read the text surrounding it. AsTeR provides this functionality to some extent.
We explained in s:changing-styles that different rules can be activated to change the type of renderings produced. Using this mechanism, we can activate a rendering rule (see fig:read-only-display-math) that speaks only the equations of a document. When a specific equation is located, rendering can be interrupted and a different rule activated. Using the browser, the listener can now move the current selection to the enclosing hierarchical unit (e.g., the containing paragraph or section) and listen to the surrounding text.