entifier">A</span> <span class="special">--&gt;</span> <span class="special">(</span><span class="identifier">a</span> <span class="special">|</span> <span class="identifier">b</span><span class="special">):</span> <span class="identifier">A</span>
</pre>
<p>
        often simplifying things significantly. If all sub expressions of an alternative
        expose the same attribute type, the overall alternative will expose exactly
        the same attribute type as well.
      </p>
</div>
<table xmlns:rev="ht