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| <div class="titlepage"><div><div><h4 class="title"> |
| <a name="fusion.tuple.class_template_tuple.tuple_helper_classes"></a><a class="link" href="tuple_helper_classes.html" title="Tuple helper classes">Tuple |
| helper classes</a> |
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| <a name="fusion.tuple.class_template_tuple.tuple_helper_classes.description"></a><h6> |
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| <a class="link" href="tuple_helper_classes.html#fusion.tuple.class_template_tuple.tuple_helper_classes.description">Description</a> |
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| <p> |
| The <a href="http://std.dkuug.dk/jtc1/sc22/wg21/docs/papers/2002/n1403.pdf" target="_top">TR1 |
| Tuple</a> provides 2 helper traits, for compile time access to the |
| tuple size, and the element types. |
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| <a name="fusion.tuple.class_template_tuple.tuple_helper_classes.specification"></a><h6> |
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| <a class="link" href="tuple_helper_classes.html#fusion.tuple.class_template_tuple.tuple_helper_classes.specification">Specification</a> |
| </h6> |
| <pre class="programlisting"><span class="identifier">tuple_size</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span> |
| </pre> |
| <p> |
| <span class="bold"><strong>Requires</strong></span>: <code class="computeroutput"><span class="identifier">T</span></code> |
| is any fusion sequence type, including <code class="computeroutput"><span class="identifier">tuple</span></code>. |
| </p> |
| <p> |
| <span class="bold"><strong>Type</strong></span>: <a href="http://www.boost.org/libs/mpl/doc/refmanual/integral-constant.html" target="_top">MPL |
| Integral Constant</a> |
| </p> |
| <p> |
| <span class="bold"><strong>Value</strong></span>: The number of elements in the sequence. |
| Equivalent to <code class="computeroutput"><a class="link" href="../../sequence/intrinsic/metafunctions/size.html" title="size"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">size</span></code></a><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">type</span></code>. |
| </p> |
| <pre class="programlisting"><span class="identifier">tuple_element</span><span class="special"><</span><span class="identifier">I</span><span class="special">,</span> <span class="identifier">T</span><span class="special">>::</span><span class="identifier">type</span> |
| </pre> |
| <p> |
| <span class="bold"><strong>Requires</strong></span>: <code class="computeroutput"><span class="identifier">T</span></code> |
| is any fusion sequence type, including <code class="computeroutput"><span class="identifier">tuple</span></code>. |
| <code class="computeroutput"><span class="number">0</span> <span class="special"><=</span> |
| <span class="identifier">I</span> <span class="special"><</span> |
| <span class="identifier">N</span></code> or the program is ill formed. |
| </p> |
| <p> |
| <span class="bold"><strong>Value</strong></span>: The type of the <code class="computeroutput"><span class="identifier">I</span></code>th |
| element of <code class="computeroutput"><span class="identifier">T</span></code>. Equivalent |
| to <code class="computeroutput"><a class="link" href="../../sequence/intrinsic/metafunctions/value_at.html" title="value_at"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">value_at</span></code></a><span class="special"><</span><span class="identifier">I</span><span class="special">,</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">type</span></code>. |
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