1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Number List Redux - list syntax</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="Spirit 2.5.8"> 8<link rel="up" href="../tutorials.html" title="Tutorials"> 9<link rel="prev" href="number_list___stuffing_numbers_into_a_std__vector.html" title="Number List - stuffing numbers into a std::vector"> 10<link rel="next" href="number_list_attribute___one_more__with_style.html" title="Number List Attribute - one more, with style"> 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="number_list___stuffing_numbers_into_a_std__vector.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../tutorials.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="number_list_attribute___one_more__with_style.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="spirit.qi.tutorials.number_list_redux___list_syntax"></a><a class="link" href="number_list_redux___list_syntax.html" title="Number List Redux - list syntax">Number 28 List Redux - list syntax</a> 29</h4></div></div></div> 30<p> 31 So far, we've been using the syntax: 32 </p> 33<pre class="programlisting"><span class="identifier">double_</span> <span class="special">>></span> <span class="special">*(</span><span class="char">','</span> <span class="special">>></span> <span class="identifier">double_</span><span class="special">)</span> 34</pre> 35<p> 36 to parse a comma-delimited list of numbers. Such lists are common in parsing 37 and Spirit provides a simpler shortcut for them. The expression above can 38 be simplified to: 39 </p> 40<pre class="programlisting"><span class="identifier">double_</span> <span class="special">%</span> <span class="char">','</span> 41</pre> 42<p> 43 read as: a list of doubles separated by <code class="computeroutput"><span class="char">','</span></code>. 44 </p> 45<p> 46 This sample, again a variation of our previous example, demonstrates just 47 that: 48 </p> 49<p> 50</p> 51<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Iterator</span><span class="special">></span> 52<span class="keyword">bool</span> <span class="identifier">parse_numbers</span><span class="special">(</span><span class="identifier">Iterator</span> <span class="identifier">first</span><span class="special">,</span> <span class="identifier">Iterator</span> <span class="identifier">last</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">double</span><span class="special">>&</span> <span class="identifier">v</span><span class="special">)</span> 53<span class="special">{</span> 54 <span class="keyword">using</span> <span class="identifier">qi</span><span class="special">::</span><span class="identifier">double_</span><span class="special">;</span> 55 <span class="keyword">using</span> <span class="identifier">qi</span><span class="special">::</span><span class="identifier">phrase_parse</span><span class="special">;</span> 56 <span class="keyword">using</span> <span class="identifier">qi</span><span class="special">::</span><span class="identifier">_1</span><span class="special">;</span> 57 <span class="keyword">using</span> <span class="identifier">ascii</span><span class="special">::</span><span class="identifier">space</span><span class="special">;</span> 58 <span class="keyword">using</span> <span class="identifier">phoenix</span><span class="special">::</span><span class="identifier">push_back</span><span class="special">;</span> 59 60 <span class="keyword">bool</span> <span class="identifier">r</span> <span class="special">=</span> <span class="identifier">phrase_parse</span><span class="special">(</span><span class="identifier">first</span><span class="special">,</span> <span class="identifier">last</span><span class="special">,</span> 61 62 <span class="comment">// Begin grammar</span> 63 <span class="special">(</span> 64 <span class="identifier">double_</span><span class="special">[</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">phoenix</span><span class="special">::</span><span class="identifier">ref</span><span class="special">(</span><span class="identifier">v</span><span class="special">),</span> <span class="identifier">_1</span><span class="special">)]</span> <span class="special">%</span> <span class="char">','</span> 65 <span class="special">)</span> 66 <span class="special">,</span> 67 <span class="comment">// End grammar</span> 68 69 <span class="identifier">space</span><span class="special">);</span> 70 71 <span class="keyword">if</span> <span class="special">(</span><span class="identifier">first</span> <span class="special">!=</span> <span class="identifier">last</span><span class="special">)</span> <span class="comment">// fail if we did not get a full match</span> 72 <span class="keyword">return</span> <span class="keyword">false</span><span class="special">;</span> 73 <span class="keyword">return</span> <span class="identifier">r</span><span class="special">;</span> 74<span class="special">}</span> 75</pre> 76<p> 77 </p> 78<p> 79 The full cpp file for this example can be found here: <a href="../../../../../example/qi/num_list3.cpp" target="_top">../../example/qi/num_list3.cpp</a> 80 </p> 81</div> 82<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 83<td align="left"></td> 84<td align="right"><div class="copyright-footer">Copyright © 2001-2011 Joel de Guzman, Hartmut Kaiser<p> 85 Distributed under the Boost Software License, Version 1.0. (See accompanying 86 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>) 87 </p> 88</div></td> 89</tr></table> 90<hr> 91<div class="spirit-nav"> 92<a accesskey="p" href="number_list___stuffing_numbers_into_a_std__vector.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../tutorials.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="number_list_attribute___one_more__with_style.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 93</div> 94</body> 95</html> 96
