diff options
| author | Anas Nashif <anas.nashif@intel.com> | 2012-10-30 12:57:26 -0700 |
|---|---|---|
| committer | Anas Nashif <anas.nashif@intel.com> | 2012-10-30 12:57:26 -0700 |
| commit | 1a78a62555be32868418fe52f8e330c9d0f95d5a (patch) | |
| tree | d3765a80e7d3b9640ec2e930743630cd6b9fce2b /doc/html/any/s02.html | |
| download | boost-1a78a62555be32868418fe52f8e330c9d0f95d5a.tar.gz boost-1a78a62555be32868418fe52f8e330c9d0f95d5a.tar.bz2 boost-1a78a62555be32868418fe52f8e330c9d0f95d5a.zip | |
Imported Upstream version 1.49.0upstream/1.49.0
Diffstat (limited to 'doc/html/any/s02.html')
| -rwxr-xr-x | doc/html/any/s02.html | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/doc/html/any/s02.html b/doc/html/any/s02.html new file mode 100755 index 0000000000..66212ee753 --- /dev/null +++ b/doc/html/any/s02.html @@ -0,0 +1,148 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>Examples</title> +<link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> +<link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> +<link rel="up" href="../any.html" title="Chapter 2. Boost.Any"> +<link rel="prev" href="../any.html" title="Chapter 2. Boost.Any"> +<link rel="next" href="reference.html" title="Reference"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> +<table cellpadding="2" width="100%"><tr> +<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td> +<td align="center"><a href="../../../index.html">Home</a></td> +<td align="center"><a href="../../../libs/libraries.htm">Libraries</a></td> +<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> +<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> +<td align="center"><a href="../../../more/index.htm">More</a></td> +</tr></table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="../any.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../any.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="reference.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> +</div> +<div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="id1028379"></a>Examples</h2></div></div></div> +<p>The following code demonstrates the syntax for using + implicit conversions to and copying of any objects:</p> +<pre class="programlisting"> +#include <list> +#include <boost/any.hpp> + +using <code class="computeroutput"><a class="link" href="../boost/any_cast.html" title="Function any_cast">boost::any_cast</a></code>; +typedef std::list<<code class="computeroutput"><a class="link" href="../boost/any.html" title="Class any">boost::any</a></code>> many; + +void append_int(many & values, int value) +{ + <code class="computeroutput"><a class="link" href="../boost/any.html" title="Class any">boost::any</a></code> to_append = value; + values.push_back(to_append); +} + +void append_string(many & values, const std::string & value) +{ + values.push_back(value); +} + +void append_char_ptr(many & values, const char * value) +{ + values.push_back(value); +} + +void append_any(many & values, const <code class="computeroutput"><a class="link" href="../boost/any.html" title="Class any">boost::any</a></code> & value) +{ + values.push_back(value); +} + +void append_nothing(many & values) +{ + values.push_back(<code class="computeroutput"><a class="link" href="../boost/any.html" title="Class any">boost::any</a></code>()); +} +</pre> +<p>The following predicates follow on from the previous + definitions and demonstrate the use of queries on any + objects:</p> +<pre class="programlisting"> +bool is_empty(const <code class="computeroutput"><a class="link" href="../boost/any.html" title="Class any">boost::any</a></code> & operand) +{ + return operand.<code class="computeroutput"><a class="link" href="../boost/any.html#id426928-bb">empty</a></code>(); +} + +bool is_int(const <code class="computeroutput"><a class="link" href="../boost/any.html" title="Class any">boost::any</a></code> & operand) +{ + return operand.<code class="computeroutput"><a class="link" href="../boost/any.html#id426952-bb">type</a></code>() == typeid(int); +} + +bool is_char_ptr(const <code class="computeroutput"><a class="link" href="../boost/any.html" title="Class any">boost::any</a></code> & operand) +{ + try + { + <code class="computeroutput"><a class="link" href="../boost/any_cast.html" title="Function any_cast">any_cast</a></code><const char *>(operand); + return true; + } + catch(const <code class="computeroutput"><a class="link" href="../boost/bad_any_cast.html" title="Class bad_any_cast">boost::bad_any_cast</a></code> &) + { + return false; + } +} + +bool is_string(const <code class="computeroutput"><a class="link" href="../boost/any.html" title="Class any">boost::any</a></code> & operand) +{ + return <code class="computeroutput"><a class="link" href="../boost/any_cast.html" title="Function any_cast">any_cast</a></code><std::string>(&operand); +} + +void count_all(many & values, std::ostream & out) +{ + out << "#empty == " + << std::count_if(values.begin(), values.end(), is_empty) << std::endl; + out << "#int == " + << std::count_if(values.begin(), values.end(), is_int) << std::endl; + out << "#const char * == " + << std::count_if(values.begin(), values.end(), is_char_ptr) << std::endl; + out << "#string == " + << std::count_if(values.begin(), values.end(), is_string) << std::endl; +} +</pre> +<p>The following type, patterned after the OMG's Property Service, defines name-value pairs for arbitrary value types:</p> +<pre class="programlisting"> +struct property +{ + property(); + property(const std::string &, const <code class="computeroutput"><a class="link" href="../boost/any.html" title="Class any">boost::any</a></code> &); + + std::string name; + <code class="computeroutput"><a class="link" href="../boost/any.html" title="Class any">boost::any</a></code> value; +}; + +typedef std::list<property> properties; +</pre> +<p>The following base class demonstrates one approach to + runtime polymorphism based callbacks that also require arbitrary + argument types. The absence of virtual member templates requires + that different solutions have different trade-offs in terms of + efficiency, safety, and generality. Using a checked variant type + offers one approach:</p> +<pre class="programlisting"> +class consumer +{ +public: + virtual void notify(const <code class="computeroutput"><a class="link" href="../boost/any.html" title="Class any">any</a></code> &) = 0; + ... +}; +</pre> +</div> +<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> +<td align="left"></td> +<td align="right"><div class="copyright-footer">Copyright © 2001 Kevlin Henney<p>Distributed under the Boost Software License, Version 1.0. + (See accompanying file <code class="filename">LICENSE_1_0.txt</code> or copy at + <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) + </p> +</div></td> +</tr></table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="../any.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../any.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="reference.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> +</div> +</body> +</html> |