1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>Versioning</title> 6<link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="../metaparse.html" title="Chapter 24. Boost.Metaparse"> 10<link rel="prev" href="user_manual.html" title="User manual"> 11<link rel="next" href="performance.html" title="Performance"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr> 15<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td> 16<td align="center"><a href="../../../index.html">Home</a></td> 17<td align="center"><a href="../../../libs/libraries.htm">Libraries</a></td> 18<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 19<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 20<td align="center"><a href="../../../more/index.htm">More</a></td> 21</tr></table> 22<hr> 23<div class="spirit-nav"> 24<a accesskey="p" href="user_manual.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../metaparse.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="performance.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 25</div> 26<div class="section"> 27<div class="titlepage"><div><div><h2 class="title" style="clear: both"> 28<a name="metaparse.versioning"></a><a class="link" href="versioning.html" title="Versioning">Versioning</a> 29</h2></div></div></div> 30<div class="toc"><dl class="toc"> 31<dt><span class="section"><a href="versioning.html#metaparse.versioning.template_classes">Template classes</a></span></dt> 32<dt><span class="section"><a href="versioning.html#metaparse.versioning.macros">Macros</a></span></dt> 33</dl></div> 34<p> 35 This section describes how the library is prepared for supporting multiple 36 (not backward compatible) changes. 37 </p> 38<div class="section"> 39<div class="titlepage"><div><div><h3 class="title"> 40<a name="metaparse.versioning.template_classes"></a><a class="link" href="versioning.html#metaparse.versioning.template_classes" title="Template classes">Template classes</a> 41</h3></div></div></div> 42<p> 43 The elements of the library are defined in the <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">metaparse</span><span class="special">::</span><span class="identifier">v1</span></code> namespace. 44 For example the <code class="computeroutput"><span class="identifier">one_char</span></code> 45 class is <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">metaparse</span><span class="special">::</span><span class="identifier">v1</span><span class="special">::</span><span class="identifier">one_char</span></code> 46 and is available after including the <code class="computeroutput"><span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">metaparse</span><span class="special">/</span><span class="identifier">v1</span><span class="special">/</span><span class="identifier">one_char</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 47 header file. 48 </p> 49<p> 50 At the same time the library provides the <code class="computeroutput"><span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">metaparse</span><span class="special">/</span><span class="identifier">one_char</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 51 header file which includes <code class="computeroutput"><span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">metaparse</span><span class="special">/</span><span class="identifier">v1</span><span class="special">/</span><span class="identifier">one_char</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 52 and contains the following: 53 </p> 54<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> 55<span class="special">{</span> 56 <span class="keyword">namespace</span> <span class="identifier">metaparse</span> 57 <span class="special">{</span> 58 <span class="keyword">using</span> <span class="identifier">v1</span><span class="special">::</span><span class="identifier">one_char</span><span class="special">;</span> 59 <span class="special">}</span> 60<span class="special">}</span> 61</pre> 62<p> 63 This makes it possible to use <code class="computeroutput"><span class="identifier">one_char</span></code> 64 as <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">metaparse</span><span class="special">::</span><span class="identifier">one_char</span></code>. 65 </p> 66<p> 67 Future versions of the library may provide other namespaces (eg. <code class="computeroutput"><span class="identifier">v2</span></code>). The header files in <code class="computeroutput"><span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">metaparse</span><span class="special">/...></span></code> provide the latest version of the 68 library. To always get version <code class="computeroutput"><span class="identifier">v1</span></code>, 69 one should use header files in <code class="computeroutput"><span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">metaparse</span><span class="special">/</span><span class="identifier">v1</span><span class="special">/...></span></code>. 70 </p> 71<p> 72 The library does not use inline namespaces to work on compilers that do not 73 support them. 74 </p> 75</div> 76<div class="section"> 77<div class="titlepage"><div><div><h3 class="title"> 78<a name="metaparse.versioning.macros"></a><a class="link" href="versioning.html#metaparse.versioning.macros" title="Macros">Macros</a> 79</h3></div></div></div> 80<p> 81 Macros defined by the library are prefixed with <code class="computeroutput"><span class="identifier">BOOST_METAPARSE_V1_</span></code>. 82 For example <code class="computeroutput"><span class="identifier">BOOST_METAPARSE_V1_STRING</span></code>. 83 It is defined in the <code class="computeroutput"><span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">metaparse</span><span class="special">/</span><span class="identifier">v1</span><span class="special">/</span><span class="identifier">string</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 84 header file. The library provides the <code class="computeroutput"><span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">metaparse</span><span class="special">/</span><span class="identifier">string</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 85 header file as well, which includes the definition of this macro and provides 86 the following definition: 87 </p> 88<pre class="programlisting"><span class="preprocessor">#define</span> <span class="identifier">BOOST_METAPARSE_STRING</span> <span class="identifier">BOOST_METAPARSE_V1_STRING</span> 89</pre> 90<p> 91 This makes it possible to use the macro as <code class="computeroutput"><span class="identifier">BOOST_METAPARSE_STRING</span></code>. 92 Future versions of the library may define other versions of this macro (eg. 93 <code class="computeroutput"><span class="identifier">BOOST_METAPARSE_V2_STRING</span></code>). 94 <code class="computeroutput"><span class="identifier">BOOST_METAPARSE_STRING</span></code> will 95 refer to the latest version. 96 </p> 97<p> 98 This versioning does not affect macros that may be overridden by the code 99 using the library. (eg. <code class="computeroutput"><span class="identifier">BOOST_METAPARSE_LIMIT_STRING_SIZE</span></code>) 100 </p> 101</div> 102</div> 103<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 104<td align="left"></td> 105<td align="right"><div class="copyright-footer">Copyright © 2015 Abel Sinkovics<p> 106 Distributed under the Boost Software License, Version 1.0. (See accompanying 107 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>) 108 </p> 109</div></td> 110</tr></table> 111<hr> 112<div class="spirit-nav"> 113<a accesskey="p" href="user_manual.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../metaparse.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="performance.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 114</div> 115</body> 116</html> 117
