PageRenderTime 48ms CodeModel.GetById 19ms RepoModel.GetById 0ms app.codeStats 0ms

/libs/functional/overloaded_function/doc/html/index.html

https://bitbucket.org/vaporoid/boost
HTML | 147 lines | 144 code | 3 blank | 0 comment | 0 complexity | 089fe44086e079e2f5c90d0367a50c1d MD5 | raw file
    

  1. <html>
    2. 

  2. <head>
    3. 

  3. <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
    4. 

  4. <title>Chapter&#160;1.&#160;Boost.Functional/OverloadedFunction 1.0.0</title>
    5. 

  5. <link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css">
    6. 

  6. <meta name="generator" content="DocBook XSL Stylesheets V1.76.1">
    7. 

  7. <link rel="home" href="index.html" title="Chapter&#160;1.&#160;Boost.Functional/OverloadedFunction 1.0.0">
    8. 

  8. <link rel="next" href="boost_functional_overloadedfunction/getting_started.html" title="Getting Started">
    9. 

  9. </head>
    10. 

  10. <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
    11. 

  11. <table cellpadding="2" width="100%"><tr>
    12. 

  12. <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td>
    13. 

  13. <td align="center"><a href="../../../../../index.html">Home</a></td>
    14. 

  14. <td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td>
    15. 

  15. <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
    16. 

  16. <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
    17. 

  17. <td align="center"><a href="../../../../../more/index.htm">More</a></td>
    18. 

  18. </tr></table>
    19. 

  19. <hr>
    20. 

  20. <div class="spirit-nav"><a accesskey="n" href="boost_functional_overloadedfunction/getting_started.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a></div>
    21. 

  21. <div class="chapter">
    22. 

  22. <div class="titlepage"><div>
    23. 

  23. <div><h2 class="title">
    24. 

  24. <a name="boost_functional_overloadedfunction"></a>Chapter&#160;1.&#160;Boost.Functional/OverloadedFunction 1.0.0</h2></div>
    25. 

  25. <div><div class="author"><h3 class="author">
    26. 

  26. <span class="firstname">Lorenzo</span> <span class="surname">Caminiti <code class="email">&lt;<a class="email" href="mailto:lorcaminiti@gmail.com">lorcaminiti@gmail.com</a>&gt;</code></span>
    27. 

  27. </h3></div></div>
    28. 

  28. <div><p class="copyright">Copyright &#169; 2011, 2012 Lorenzo Caminiti</p></div>
    29. 

  29. <div><div class="legalnotice">
    30. 

  30. <a name="boost_functional_overloadedfunction.legal"></a><p>
    31. 

  31.         Distributed under the Boost Software License, Version 1.0 (see accompanying
    32. 

  32.         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>)
    33. 

  33.       </p>
    34. 

  34. </div></div>
    35. 

  35. </div></div>
    36. 

  36. <div class="toc">
    37. 

  37. <p><b>Table of Contents</b></p>
    38. 

  38. <dl>
    39. 

  39. <dt><span class="section"><a href="index.html#boost_functional_overloadedfunction.introduction">Introduction</a></span></dt>
    40. 

  40. <dt><span class="section"><a href="boost_functional_overloadedfunction/getting_started.html">Getting
    41. 

  41.     Started</a></span></dt>
    42. 

  42. <dd><dl>
    43. 

  43. <dt><span class="section"><a href="boost_functional_overloadedfunction/getting_started.html#boost_functional_overloadedfunction.getting_started.compilers_and_platforms">Compilers
    44. 

  44.       and Platforms</a></span></dt>
    45. 

  45. <dt><span class="section"><a href="boost_functional_overloadedfunction/getting_started.html#boost_functional_overloadedfunction.getting_started.installation">Installation</a></span></dt>
    46. 

  46. </dl></dd>
    47. 

  47. <dt><span class="section"><a href="boost_functional_overloadedfunction/tutorial.html">Tutorial</a></span></dt>
    48. 

  48. <dd><dl>
    49. 

  49. <dt><span class="section"><a href="boost_functional_overloadedfunction/tutorial.html#boost_functional_overloadedfunction.tutorial.overloading">Overloading</a></span></dt>
    50. 

  50. <dt><span class="section"><a href="boost_functional_overloadedfunction/tutorial.html#boost_functional_overloadedfunction.tutorial.without_function_types">Without
    51. 

  51.       Function Types</a></span></dt>
    52. 

  52. </dl></dd>
    53. 

  53. <dt><span class="section"><a href="reference.html">Reference</a></span></dt>
    54. 

  54. <dd><dl>
    55. 

  55. <dt><span class="section"><a href="reference.html#header.boost.functional.overloaded_function_hpp">Header &lt;boost/functional/overloaded_function.hpp&gt;</a></span></dt>
    56. 

  56. <dt><span class="section"><a href="reference.html#header.boost.functional.overloaded_function.config_hpp">Header &lt;boost/functional/overloaded_function/config.hpp&gt;</a></span></dt>
    57. 

  57. </dl></dd>
    58. 

  58. <dt><span class="section"><a href="boost_functional_overloadedfunction/acknowledgments.html">Acknowledgments</a></span></dt>
    59. 

  59. </dl>
    60. 

  60. </div>
    61. 

  61. <p>
    62. 

  62.     This library allows to overload different functions into a single function object.
    63. 

  63.   </p>
    64. 

  64. <div class="section boost_functional_overloadedfunction_introduction">
    65. 

  65. <div class="titlepage"><div><div><h2 class="title" style="clear: both">
    66. 

  66. <a name="boost_functional_overloadedfunction.introduction"></a><a class="link" href="index.html#boost_functional_overloadedfunction.introduction" title="Introduction">Introduction</a>
    67. 

  67. </h2></div></div></div>
    68. 

  68. <p>
    69. 

  69.       Consider the following functions which have distinct signatures:
    70. 

  70.     </p>
    71. 

  71. <p>
    72. 

  72. </p>
    73. 

  73. <pre class="programlisting"><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&amp;</span> <span class="identifier">identity_s</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&amp;</span> <span class="identifier">x</span><span class="special">)</span> <span class="comment">// Function (as pointer).</span>
    74. 

  74.     <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">x</span><span class="special">;</span> <span class="special">}</span>
    75. 

  75. 

  76. <span class="keyword">int</span> <span class="identifier">identity_i_impl</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">x</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">x</span><span class="special">;</span> <span class="special">}</span>
    77. 

  77. <span class="keyword">int</span> <span class="special">(&amp;</span><span class="identifier">identity_i</span><span class="special">)(</span><span class="keyword">int</span><span class="special">)</span> <span class="special">=</span> <span class="identifier">identity_i_impl</span><span class="special">;</span> <span class="comment">// Function reference.</span>
    78. 

  78. 

  79. <span class="keyword">double</span> <span class="identifier">identity_d_impl</span><span class="special">(</span><span class="keyword">double</span> <span class="identifier">x</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">x</span><span class="special">;</span> <span class="special">}</span>
    80. 

  80. <span class="identifier">boost</span><span class="special">::</span><span class="identifier">function</span><span class="special">&lt;</span><span class="keyword">double</span> <span class="special">(</span><span class="keyword">double</span><span class="special">)&gt;</span> <span class="identifier">identity_d</span> <span class="special">=</span> <span class="identifier">identity_d_impl</span><span class="special">;</span> <span class="comment">// Functor.</span>
    81. 

  81. </pre>
    82. 

  82. <p>
    83. 

  83.     </p>
    84. 

  84. <p>
    85. 

  85.       Instead of calling them using their separate names (here <code class="computeroutput"><span class="identifier">BOOST_TEST</span></code>
    86. 

  86.       is equivalent to <code class="computeroutput"><span class="identifier">assert</span></code>):
    87. 

  87.       <sup>[<a name="boost_functional_overloadedfunction.introduction.f0" href="#ftn.boost_functional_overloadedfunction.introduction.f0" class="footnote">1</a>]</sup>
    88. 

  88.     </p>
    89. 

  89. <p>
    90. 

  90. </p>
    91. 

  91. <pre class="programlisting"><span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">identity_s</span><span class="special">(</span><span class="string">"abc"</span><span class="special">)</span> <span class="special">==</span> <span class="string">"abc"</span><span class="special">);</span>
    92. 

  92. <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">identity_i</span><span class="special">(</span><span class="number">123</span><span class="special">)</span> <span class="special">==</span> <span class="number">123</span><span class="special">);</span>
    93. 

  93. <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">identity_d</span><span class="special">(</span><span class="number">1.23</span><span class="special">)</span> <span class="special">==</span> <span class="number">1.23</span><span class="special">);</span>
    94. 

  94. </pre>
    95. 

  95. <p>
    96. 

  96.     </p>
    97. 

  97. <p>
    98. 

  98.       It is possible to use this library to create a single <a href="http://en.wikipedia.org/wiki/Function_overloading" target="_top">overloaded</a>
    99. 

  99.       function object (or <a href="http://en.wikipedia.org/wiki/Functor" target="_top">functor</a>)
    100. 

  100.       named <code class="computeroutput"><span class="identifier">identity</span></code> that aggregates
    101. 

  101.       together the calls to the specific functions (see also <a href="../../test/functor.cpp" target="_top"><code class="literal">functor.cpp</code></a>
    102. 

  102.       and <a href="../../test/identity.hpp" target="_top"><code class="literal">identity.hpp</code></a>):
    103. 

  103.     </p>
    104. 

  104. <p>
    105. 

  105. </p>
    106. 

  106. <pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">overloaded_function</span><span class="special">&lt;</span>
    107. 

  107.       <span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&amp;</span> <span class="special">(</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&amp;)</span>
    108. 

  108.     <span class="special">,</span> <span class="keyword">int</span> <span class="special">(</span><span class="keyword">int</span><span class="special">)</span>
    109. 

  109.     <span class="special">,</span> <span class="keyword">double</span> <span class="special">(</span><span class="keyword">double</span><span class="special">)</span>
    110. 

  110. <span class="special">&gt;</span> <span class="identifier">identity</span><span class="special">(</span><span class="identifier">identity_s</span><span class="special">,</span> <span class="identifier">identity_i</span><span class="special">,</span> <span class="identifier">identity_d</span><span class="special">);</span>
    111. 

  111. 

  112. <span class="comment">// All calls via single `identity` function.</span>
    113. 

  113. <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">identity</span><span class="special">(</span><span class="string">"abc"</span><span class="special">)</span> <span class="special">==</span> <span class="string">"abc"</span><span class="special">);</span>
    114. 

  114. <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">identity</span><span class="special">(</span><span class="number">123</span><span class="special">)</span> <span class="special">==</span> <span class="number">123</span><span class="special">);</span>
    115. 

  115. <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">identity</span><span class="special">(</span><span class="number">1.23</span><span class="special">)</span> <span class="special">==</span> <span class="number">1.23</span><span class="special">);</span>
    116. 

  116. </pre>
    117. 

  117. <p>
    118. 

  118.     </p>
    119. 

  119. <p>
    120. 

  120.       Note how the functions are called via a single overloaded function object
    121. 

  121.       <code class="computeroutput"><span class="identifier">identity</span></code> instead of using their
    122. 

  122.       different names <code class="computeroutput"><span class="identifier">identity_s</span></code>,
    123. 

  123.       <code class="computeroutput"><span class="identifier">identity_i</span></code>, and <code class="computeroutput"><span class="identifier">identity_d</span></code>.
    124. 

  124.     </p>
    125. 

  125. </div>
    126. 

  126. <div class="footnotes">
    127. 

  127. <br><hr width="100" align="left">
    128. 

  128. <div class="footnote"><p><sup>[<a id="ftn.boost_functional_overloadedfunction.introduction.f0" href="#boost_functional_overloadedfunction.introduction.f0" class="para">1</a>] </sup>
    129. 

  129.         In most of the examples presented in this documentation, the Boost.Detail/LightweightTest
    130. 

  130.         (<code class="literal">boost/detail/lightweight_test.hpp</code>) macro <code class="computeroutput"><span class="identifier">BOOST_TEST</span></code> is used to check correctness
    131. 

  131.         conditions (conceptually similar to <code class="computeroutput"><span class="identifier">assert</span></code>).
    132. 

  132.         A failure of the checked condition does not abort the execution of the program,
    133. 

  133.         it will instead make <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">report_errors</span></code>
    134. 

  134.         return a non-zero program exit code. Using Boost.Detail/LightweightTest allows
    135. 

  135.         to add the examples to the library regression tests so to make sure that
    136. 

  136.         they always compile and run correctly.
    137. 

  137.       </p></div>
    138. 

  138. </div>
    139. 

  139. </div>
    140. 

  140. <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
    141. 

  141. <td align="left"><p><small>Last revised: April 28, 2012 at 02:19:13 GMT</small></p></td>
    142. 

  142. <td align="right"><div class="copyright-footer"></div></td>
    143. 

  143. </tr></table>
    144. 

  144. <hr>
    145. 

  145. <div class="spirit-nav"><a accesskey="n" href="boost_functional_overloadedfunction/getting_started.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a></div>
    146. 

  146. </body>
    147. 

  147. </html>
    148. 

  148.