1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Terminology and style guidelines</title> 5<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../index.html" title="Chapter 1. Range 2.0"> 8<link rel="up" href="../index.html" title="Chapter 1. Range 2.0"> 9<link rel="prev" href="reference/extending/method_3/method_3_2.html" title="Method 3.2: Implement a Range Adaptor with arguments"> 10<link rel="next" href="headers.html" title="Library Headers"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="reference/extending/method_3/method_3_2.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="headers.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h2 class="title" style="clear: both"> 27<a name="range.style_guide"></a><a class="link" href="style_guide.html" title="Terminology and style guidelines">Terminology and style guidelines</a> 28</h2></div></div></div> 29<p> 30 The use of a consistent terminology is as important for <a class="link" href="concepts.html" title="Range Concepts">Ranges</a> 31 and range-based algorithms as it is for iterators and iterator-based algorithms. 32 If a conventional set of names are adopted, we can avoid misunderstandings 33 and write generic function prototypes that are <span class="bold"><strong><span class="emphasis"><em>self-documenting</em></span></strong></span>. 34 </p> 35<p> 36 Since ranges are characterized by a specific underlying iterator type, we get 37 a type of range for each type of iterator. Hence we can speak of the following 38 types of ranges: 39 </p> 40<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 41<li class="listitem"> 42 <span class="bold"><strong><span class="emphasis"><em>Value access</em></span></strong></span> category: 43 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "> 44<li class="listitem"> 45 Readable Range 46 </li> 47<li class="listitem"> 48 Writeable Range 49 </li> 50<li class="listitem"> 51 Swappable Range 52 </li> 53<li class="listitem"> 54 Lvalue Range 55 </li> 56</ul></div> 57 </li> 58<li class="listitem"> 59 <span class="bold"><strong><span class="emphasis"><em>Traversal</em></span></strong></span> category: 60 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "> 61<li class="listitem"> 62 <a class="link" href="concepts/single_pass_range.html" title="Single Pass Range">Single Pass Range</a> 63 </li> 64<li class="listitem"> 65 <a class="link" href="concepts/forward_range.html" title="Forward Range">Forward Range</a> 66 </li> 67<li class="listitem"> 68 <a class="link" href="concepts/bidirectional_range.html" title="Bidirectional Range">Bidirectional 69 Range</a> 70 </li> 71<li class="listitem"> 72 <a class="link" href="concepts/random_access_range.html" title="Random Access Range">Random Access 73 Range</a> 74 </li> 75</ul></div> 76 </li> 77</ul></div> 78<p> 79 Notice how we have used the categories from the <a href="../../../../../libs/iterator/doc/new-iter-concepts.html" target="_top">new 80 style iterators</a>. 81 </p> 82<p> 83 Notice that an iterator (and therefore an range) has one <span class="bold"><strong><span class="emphasis"><em>traversal</em></span></strong></span> 84 property and one or more properties from the <span class="bold"><strong><span class="emphasis"><em>value 85 access</em></span></strong></span> category. So in reality we will mostly talk about 86 mixtures such as 87 </p> 88<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 89<li class="listitem"> 90 Random Access Readable Writeable Range 91 </li> 92<li class="listitem"> 93 Forward Lvalue Range 94 </li> 95</ul></div> 96<p> 97 By convention, we should always specify the <span class="bold"><strong><span class="emphasis"><em>traversal</em></span></strong></span> 98 property first as done above. This seems reasonable since there will only be 99 one <span class="bold"><strong><span class="emphasis"><em>traversal</em></span></strong></span> property, 100 but perhaps many <span class="bold"><strong><span class="emphasis"><em>value access</em></span></strong></span> 101 properties. 102 </p> 103<p> 104 It might, however, be reasonable to specify only one category if the other 105 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 106 from a Forward Range. This means that we do not care about what <span class="bold"><strong><span class="emphasis"><em>value 107 access</em></span></strong></span> properties the Range has. Similarly, a Readable 108 Range will be one that has the lowest possible <span class="bold"><strong><span class="emphasis"><em>traversal</em></span></strong></span> 109 property (Single Pass). 110 </p> 111<p> 112 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 113 specify the interface of since both <span class="bold"><strong><span class="emphasis"><em>traversal</em></span></strong></span> 114 and <span class="bold"><strong><span class="emphasis"><em>value access</em></span></strong></span> properties 115 must be exactly defined. The iterator-based version looks like this: 116 </p> 117<p> 118</p> 119<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> 120<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> 121 <span class="identifier">RandomAccessTraversalReadableWritableIterator</span> <span class="identifier">last</span> <span class="special">);</span> 122</pre> 123<p> 124 </p> 125<p> 126 For ranges the interface becomes 127 </p> 128<p> 129</p> 130<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> 131<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> 132</pre> 133<p> 134 </p> 135</div> 136<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 137<td align="left"></td> 138<td align="right"><div class="copyright-footer">Copyright © 2003-2010 Thorsten Ottosen, 139 Neil Groves<p> 140 Distributed under the Boost Software License, Version 1.0. (See accompanying 141 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>) 142 </p> 143</div></td> 144</tr></table> 145<hr> 146<div class="spirit-nav"> 147<a accesskey="p" href="reference/extending/method_3/method_3_2.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="headers.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 148</div> 149</body> 150</html> 151
