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| <div class="titlepage"><div><div><h2 class="title" style="clear: both"> |
| <a name="range.style_guide"></a><a class="link" href="style_guide.html" title="Terminology and style guidelines"> Terminology and style guidelines</a> |
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| <p> |
| The use of a consistent terminology is as important for <a class="link" href="concepts.html" title="Range Concepts">Ranges</a> |
| and range-based algorithms as it is for iterators and iterator-based algorithms. |
| If a conventional set of names are adopted, we can avoid misunderstandings |
| and write generic function prototypes that are <span class="bold"><strong><span class="emphasis"><em>self-documenting</em></span></strong></span>. |
| </p> |
| <p> |
| Since ranges are characterized by a specific underlying iterator type, we get |
| a type of range for each type of iterator. Hence we can speak of the following |
| types of ranges: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"> |
| <span class="bold"><strong><span class="emphasis"><em>Value access</em></span></strong></span> category: |
| <div class="itemizedlist"><ul class="itemizedlist" type="circle"> |
| <li class="listitem"> |
| Readable Range |
| </li> |
| <li class="listitem"> |
| Writeable Range |
| </li> |
| <li class="listitem"> |
| Swappable Range |
| </li> |
| <li class="listitem"> |
| Lvalue Range |
| </li> |
| </ul></div> |
| </li> |
| <li class="listitem"> |
| <span class="bold"><strong><span class="emphasis"><em>Traversal</em></span></strong></span> category: |
| <div class="itemizedlist"><ul class="itemizedlist" type="circle"> |
| <li class="listitem"> |
| <a class="link" href="concepts/single_pass_range.html" title="Single Pass Range">Single Pass Range</a> |
| </li> |
| <li class="listitem"> |
| <a class="link" href="concepts/forward_range.html" title="Forward Range">Forward Range</a> |
| </li> |
| <li class="listitem"> |
| <a class="link" href="concepts/bidirectional_range.html" title="Bidirectional Range">Bidirectional |
| Range</a> |
| </li> |
| <li class="listitem"> |
| <a class="link" href="concepts/random_access_range.html" title="Random Access Range">Random Access |
| Range</a> |
| </li> |
| </ul></div> |
| </li> |
| </ul></div> |
| <p> |
| Notice how we have used the categories from the <a href="../../../../../libs/iterator/doc/new-iter-concepts.html" target="_top">new |
| style iterators</a>. |
| </p> |
| <p> |
| Notice that an iterator (and therefore an range) has one <span class="bold"><strong><span class="emphasis"><em>traversal</em></span></strong></span> |
| property and one or more properties from the <span class="bold"><strong><span class="emphasis"><em>value |
| access</em></span></strong></span> category. So in reality we will mostly talk about |
| mixtures such as |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"> |
| Random Access Readable Writeable Range |
| </li> |
| <li class="listitem"> |
| Forward Lvalue Range |
| </li> |
| </ul></div> |
| <p> |
| By convention, we should always specify the <span class="bold"><strong><span class="emphasis"><em>traversal</em></span></strong></span> |
| property first as done above. This seems reasonable since there will only be |
| one <span class="bold"><strong><span class="emphasis"><em>traversal</em></span></strong></span> property, |
| but perhaps many <span class="bold"><strong><span class="emphasis"><em>value access</em></span></strong></span> |
| properties. |
| </p> |
| <p> |
| It might, however, be reasonable to specify only one category if the other |
| category does not matter. For example, the <a class="link" href="reference/utilities/iterator_range.html" title="Class iterator_range"><code class="computeroutput"><span class="identifier">iterator_range</span></code></a> can be constructed |
| from a Forward Range. This means that we do not care about what <span class="bold"><strong><span class="emphasis"><em>value |
| access</em></span></strong></span> properties the Range has. Similarly, a Readable |
| Range will be one that has the lowest possible <span class="bold"><strong><span class="emphasis"><em>traversal</em></span></strong></span> |
| property (Single Pass). |
| </p> |
| <p> |
| As another example, consider how we specify the interface of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">sort</span><span class="special">()</span></code>. Algorithms are usually more cumbersome to |
| specify the interface of since both <span class="bold"><strong><span class="emphasis"><em>traversal</em></span></strong></span> |
| and <span class="bold"><strong><span class="emphasis"><em>value access</em></span></strong></span> properties |
| must be exactly defined. The iterator-based version looks like this: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">class</span> <span class="identifier">RandomAccessTraversalReadableWritableIterator</span> <span class="special">></span> |
| <span class="keyword">void</span> <span class="identifier">sort</span><span class="special">(</span> <span class="identifier">RandomAccessTraversalReadableWritableIterator</span> <span class="identifier">first</span><span class="special">,</span> |
| <span class="identifier">RandomAccessTraversalReadableWritableIterator</span> <span class="identifier">last</span> <span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| For ranges the interface becomes |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">class</span> <span class="identifier">RandomAccessReadableWritableRange</span> <span class="special">></span> |
| <span class="keyword">void</span> <span class="identifier">sort</span><span class="special">(</span> <span class="identifier">RandomAccessReadableWritableRange</span><span class="special">&</span> <span class="identifier">r</span> <span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
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| <td align="right"><div class="copyright-footer">Copyright © 2003 -2010 Thorsten Ottosen, Neil Groves<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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