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| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="boost_icl.function_reference.segmentational_fineness"></a><a class="link" href="segmentational_fineness.html" title="Segmentational Fineness">Segmentational |
| Fineness</a> |
| </h3></div></div></div> |
| <p> |
| For overloading tables on infix operators, we need to break down <code class="computeroutput"><a class="link" href="../../boost/icl/interval_set.html" title="Class template interval_set">interval_sets</a></code> and <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_maps</a></code> |
| to the specific class templates |
| </p> |
| <a name="ph_def_S1"></a><a name="ph_def_S2"></a><a name="ph_def_S3"></a><a name="ph_def_M1"></a><a name="ph_def_M3"></a><div class="informaltable"><table class="table"> |
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| <span class="bold"><strong>S1</strong></span> |
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| <p> |
| <code class="computeroutput"><a class="link" href="../../boost/icl/interval_set.html" title="Class template interval_set">interval_set</a></code> |
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| <p> |
| <span class="bold"><strong>S2</strong></span> |
| </p> |
| </td> |
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| <p> |
| <code class="computeroutput"><a class="link" href="../../boost/icl/separate_interval_set.html" title="Class template separate_interval_set">separate_interval_set</a></code> |
| </p> |
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| <p> |
| <span class="bold"><strong>S3</strong></span> |
| </p> |
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| <p> |
| <code class="computeroutput"><a class="link" href="../../boost/icl/split_interval_set.html" title="Class template split_interval_set">split_interval_set</a></code> |
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| <span class="bold"><strong>M1</strong></span> |
| </p> |
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| <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code> |
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| <span class="bold"><strong>M3</strong></span> |
| </p> |
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| <p> |
| <code class="computeroutput"><a class="link" href="../../boost/icl/split_interval_map.html" title="Class template split_interval_map">split_interval_map</a></code> |
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| choosing <span class="bold"><strong>Si</strong></span> and <span class="bold"><strong>Mi</strong></span> |
| as placeholders. |
| </p> |
| <p> |
| The indices <span class="bold"><strong>i</strong></span> of <span class="bold"><strong>Si</strong></span> |
| and <span class="bold"><strong>Mi</strong></span> represent a property called <span class="emphasis"><em><span class="bold"><strong>segmentational fineness</strong></span></em></span> or short <span class="emphasis"><em><span class="bold"><strong>fineness</strong></span></em></span>, which is a <span class="emphasis"><em><span class="bold"><strong>type trait</strong></span></em></span> on interval containers. |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup><col></colgroup> |
| <thead><tr><th> |
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| </p> |
| </th></tr></thead> |
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| <p> |
| <code class="computeroutput"><span class="identifier">segmentational_fineness</span><span class="special"><</span></code><span class="bold"><strong>Si</strong></span><code class="computeroutput"><span class="special">>::</span><span class="identifier">value</span></code> |
| == <span class="bold"><strong>i</strong></span> |
| </p> |
| </td></tr> |
| <tr><td> |
| <p> |
| <code class="computeroutput"><span class="identifier">segmentational_fineness</span><span class="special"><</span></code><span class="bold"><strong>Mi</strong></span><code class="computeroutput"><span class="special">>::</span><span class="identifier">value</span></code> |
| == <span class="bold"><strong>i</strong></span> |
| </p> |
| </td></tr> |
| </tbody> |
| </table></div> |
| <p> |
| Segmentational fineness represents the fact, that for interval containers |
| holding the same elements, a splitting interval container may contain more |
| segments as a separating container which in turn may contain more segments |
| than a joining one. So for an |
| </p> |
| <pre class="programlisting"><span class="keyword">operator</span> <span class="special">></span> |
| </pre> |
| <p> |
| where |
| </p> |
| <pre class="programlisting"><span class="identifier">x</span> <span class="special">></span> <span class="identifier">y</span> <span class="comment">// means that |
| </span><span class="identifier">x</span> <span class="identifier">is_finer_than</span> <span class="identifier">y</span> |
| |
| <span class="comment">// we have |
| </span> |
| <span class="identifier">finer</span> <span class="identifier">coarser</span> |
| <span class="identifier">split_interval_set</span> <span class="identifier">interval_set</span> |
| <span class="special">></span> <span class="identifier">separate_interval_set</span> <span class="special">></span> |
| <span class="identifier">split_interval_map</span> <span class="identifier">interval_map</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| This relation is needed to resolve the instantiation of infix operators e.g. |
| <code class="computeroutput"><span class="identifier">T</span> <span class="keyword">operator</span> |
| <span class="special">+</span> <span class="special">(</span><span class="identifier">P</span><span class="special">,</span> <span class="identifier">Q</span><span class="special">)</span></code> for two interval container types <code class="computeroutput"><span class="identifier">P</span></code> and <code class="computeroutput"><span class="identifier">Q</span></code>. |
| If both <code class="computeroutput"><span class="identifier">P</span></code> and <code class="computeroutput"><span class="identifier">Q</span></code> are candidates for the result type <code class="computeroutput"><span class="identifier">T</span></code>, one of them must be chosen by the compiler. |
| We choose the type that is segmentational finer as result type <code class="computeroutput"><span class="identifier">T</span></code>. This way we do not loose the <span class="emphasis"><em><span class="bold"><strong>segment information</strong></span></em></span> that is stored in the |
| <span class="emphasis"><em><span class="bold"><strong>finer</strong></span></em></span> one of the container |
| types <code class="computeroutput"><span class="identifier">P</span></code> and <code class="computeroutput"><span class="identifier">Q</span></code>. |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="comment">// overload tables for |
| </span><span class="identifier">T</span> <span class="keyword">operator</span> <span class="special">+</span> <span class="special">(</span><span class="identifier">T</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">P</span><span class="special">&)</span> |
| <span class="identifier">T</span> <span class="keyword">operator</span> <span class="special">+</span> <span class="special">(</span><span class="keyword">const</span> <span class="identifier">P</span><span class="special">&,</span> <span class="identifier">T</span><span class="special">)</span> |
| |
| <span class="identifier">element</span> <span class="identifier">containers</span><span class="special">:</span> <span class="identifier">interval</span> <span class="identifier">containers</span><span class="special">:</span> |
| <span class="special">+</span> <span class="special">|</span> <span class="identifier">e</span> <span class="identifier">b</span> <span class="identifier">s</span> <span class="identifier">m</span> <span class="special">+</span> <span class="special">|</span> <span class="identifier">e</span> <span class="identifier">i</span> <span class="identifier">b</span> <span class="identifier">p</span> <span class="identifier">S1</span> <span class="identifier">S2</span> <span class="identifier">S3</span> <span class="identifier">M1</span> <span class="identifier">M3</span> |
| <span class="special">---+--------</span> <span class="special">---+---------------------------</span> |
| <span class="identifier">e</span> <span class="special">|</span> <span class="identifier">s</span> <span class="identifier">e</span> <span class="special">|</span> <span class="identifier">S1</span> <span class="identifier">S2</span> <span class="identifier">S3</span> |
| <span class="identifier">b</span> <span class="special">|</span> <span class="identifier">m</span> <span class="identifier">i</span> <span class="special">|</span> <span class="identifier">S1</span> <span class="identifier">S2</span> <span class="identifier">S3</span> |
| <span class="identifier">s</span> <span class="special">|</span> <span class="identifier">s</span> <span class="identifier">s</span> <span class="identifier">b</span> <span class="special">|</span> <span class="identifier">M1</span> <span class="identifier">M3</span> |
| <span class="identifier">m</span> <span class="special">|</span> <span class="identifier">m</span> <span class="identifier">m</span> <span class="identifier">p</span> <span class="special">|</span> <span class="identifier">M1</span> <span class="identifier">M3</span> |
| <span class="identifier">S1</span> <span class="special">|</span> <span class="identifier">S1</span> <span class="identifier">S1</span> <span class="identifier">S1</span> <span class="identifier">S2</span> <span class="identifier">S3</span> |
| <span class="identifier">S2</span> <span class="special">|</span> <span class="identifier">S2</span> <span class="identifier">S2</span> <span class="identifier">S2</span> <span class="identifier">S2</span> <span class="identifier">S3</span> |
| <span class="identifier">S3</span> <span class="special">|</span> <span class="identifier">S3</span> <span class="identifier">S3</span> <span class="identifier">S3</span> <span class="identifier">S3</span> <span class="identifier">S3</span> |
| <span class="identifier">M1</span> <span class="special">|</span> <span class="identifier">M1</span> <span class="identifier">M1</span> <span class="identifier">M1</span> <span class="identifier">M3</span> |
| <span class="identifier">M3</span> <span class="special">|</span> <span class="identifier">M3</span> <span class="identifier">M3</span> <span class="identifier">M3</span> <span class="identifier">M3</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| So looking up a type combination for e.g. <code class="computeroutput"><span class="identifier">T</span> |
| <span class="keyword">operator</span> <span class="special">+</span> |
| <span class="special">(</span><span class="identifier">interval_map</span><span class="special">,</span> <span class="identifier">split_interval_map</span><span class="special">)</span></code> which is equivalent to <code class="computeroutput"><span class="identifier">T</span> |
| <span class="keyword">operator</span> <span class="special">+</span> |
| <span class="special">(</span><span class="identifier">M1</span><span class="special">,</span> <span class="identifier">M3</span><span class="special">)</span></code> |
| we find for row type <code class="computeroutput"><span class="identifier">M1</span></code> and |
| column type <code class="computeroutput"><span class="identifier">M3</span></code> that <code class="computeroutput"><span class="identifier">M3</span></code> will be assigned as result type, because |
| <code class="computeroutput"><span class="identifier">M3</span></code> is finer than <code class="computeroutput"><span class="identifier">M1</span></code>. So this type combination will result |
| in choosing this |
| </p> |
| <pre class="programlisting"><span class="identifier">split_interval_map</span> <span class="keyword">operator</span> <span class="special">+</span> <span class="special">(</span><span class="keyword">const</span> <span class="identifier">interval_map</span><span class="special">&,</span> <span class="identifier">split_interval_map</span><span class="special">)</span> |
| </pre> |
| <p> |
| implementation by the compiler. |
| </p> |
| </div> |
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| <td align="right"><div class="copyright-footer">Copyright © 2007 -2010 Joachim Faulhaber<br>Copyright © 1999 -2006 Cortex Software GmbH<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) |
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