 not have a
default text reading direction. Any time a reading direction is necessary,
for example when text is to be displayed, or when a
writing-direction-dependent value is to be interpreted, the reading
direction must be explicitly specified. Where possible, such as in <code>switch</code>
statements, the right-to-left case is listed first, to avoid the impression
that it is an afterthought.</p>
<p>At the higher levels (specifically starting at the widgets library), an
ambient <code>Directionality</code>