boost-react-native-bundle

<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="generator" content="Docutils 0.7: http://docutils.sourceforge.net/" /> <title>The MPL Reference Manual: Numeric Metafunction</title> <link rel="stylesheet" href="../style.css" type="text/css" /> </head> <body class="docframe refmanual"> <table class="header"><tr class="header"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./tag-dispatched-metafunction.html" class="navigation-link">Prev</a> <a href="./trivial-metafunction.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./tag-dispatched-metafunction.html" class="navigation-link">Back</a> <a href="./trivial-metafunction.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./metafunctions-concepts.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> <td class="header-group page-location"><a href="../refmanual.html" class="navigation-link">Front Page</a> / <a href="./metafunctions.html" class="navigation-link">Metafunctions</a> / <a href="./metafunctions-concepts.html" class="navigation-link">Concepts</a> / <a href="./numeric-metafunction.html" class="navigation-link">Numeric Metafunction</a></td> </tr></table><div class="header-separator"></div> <div class="section" id="numeric-metafunction"> <h1><a class="toc-backref" href="./metafunctions-concepts.html#id1517">Numeric Metafunction</a></h1> <div class="section" id="id847"> <h3><a class="subsection-title" href="#description" name="description">Description</a></h3> <p>A <a class="reference internal" href="./numeric-metafunction.html">Numeric Metafunction</a> is a <a class="reference internal" href="./tag-dispatched-metafunction.html">Tag Dispatched Metafunction</a> that provides a built-in infrastructure for easy implementation of mixed-type operations.</p> </div> <div class="section" id="id848"> <h3><a class="subsection-title" href="#expression-requirements" name="expression-requirements">Expression requirements</a></h3> <p>In the following table and subsequent specifications, <tt class="literal"><span class="pre">op</span></tt> is a placeholder token for the actual <a class="reference internal" href="./numeric-metafunction.html">Numeric Metafunction</a>'s name, and <tt class="literal"><span class="pre">x</span></tt>, <tt class="literal"><span class="pre">y</span></tt> and <em>x</em><sub>1</sub>,<em>x</em><sub>2</sub>,... <em>x</em><sub>n</sub> are arbitrary numeric types.</p> <table border="1" class="docutils table"> <colgroup> <col width="46%" /> <col width="25%" /> <col width="29%" /> </colgroup> <thead valign="bottom"> <tr><th class="head">Expression</th> <th class="head">Type</th> <th class="head">Complexity</th> </tr> </thead> <tbody valign="top"> <tr><td><tt class="literal"><span class="pre">op_tag<x>::type</span></tt></td> <td><a class="reference internal" href="./integral-constant.html">Integral Constant</a></td> <td>Amortized constant time.</td> </tr> <tr><td><pre class="first last literal-block"> op_impl< op_tag<x>::type , op_tag<y>::type >::<a href="./apply.html" class="identifier">apply</a><x,y>::type </pre> </td> <td>Any type</td> <td>Unspecified.</td> </tr> <tr><td><tt class="literal"><span class="pre">op<</span></tt><em>x</em><sub>1</sub>,<em>x</em><sub>2</sub>,... <em>x</em><sub>n</sub><tt class="literal"><span class="pre">>::type</span></tt></td> <td>Any type</td> <td>Unspecified.</td> </tr> </tbody> </table> </div> <div class="section" id="id849"> <h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> <pre class="literal-block"> typedef op_tag<x>::type tag; </pre> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><tt class="literal"><span class="pre">tag</span></tt> is a tag type for <tt class="literal"><span class="pre">x</span></tt> for <tt class="literal"><span class="pre">op</span></tt>. <tt class="literal"><span class="pre">tag::value</span></tt> is <tt class="literal"><span class="pre">x</span></tt>'s <em>conversion rank</em>.</td> </tr> </tbody> </table>  <pre class="literal-block"> typedef op_impl< op_tag<x>::type , op_tag<y>::type >::<a href="./apply.html" class="identifier">apply</a><x,y>::type r; </pre> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><tt class="literal"><span class="pre">r</span></tt> is the result of <tt class="literal"><span class="pre">op</span></tt> application on arguments <tt class="literal"><span class="pre">x</span></tt> and <tt class="literal"><span class="pre">y</span></tt>.</td> </tr> </tbody> </table>  <pre class="literal-block"> typedef op<<em>x</em><sub>1</sub>,<em>x</em><sub>2</sub>,... <em>x</em><sub>n</sub>>::type r; </pre> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><tt class="literal"><span class="pre">r</span></tt> is the result of <tt class="literal"><span class="pre">op</span></tt> application on arguments <em>x</em><sub>1</sub>,<em>x</em><sub>2</sub>,... <em>x</em><sub>n</sub>.</td> </tr> </tbody> </table> </div> <div class="section" id="id850"> <h3><a class="subsection-title" href="#example" name="example">Example</a></h3> <pre class="literal-block"> struct complex_tag : <a href="./int.html" class="identifier">int_</a><10> {}; template< typename Re, typename Im > struct complex { typedef complex_tag tag; typedef complex type; typedef Re real; typedef Im imag; }; template< typename C > struct real : C::real {}; template< typename C > struct imag : C::imag {}; namespace boost { namespace mpl { template<> struct plus_impl< complex_tag,complex_tag > { template< typename N1, typename N2 > struct <a href="./apply.html" class="identifier">apply</a> : complex< <a href="./plus.html" class="identifier">plus</a>< typename N1::real, typename N2::real > , <a href="./plus.html" class="identifier">plus</a>< typename N1::imag, typename N2::imag > > { }; }; }} typedef complex< <a href="./int.html" class="identifier">int_</a><5>, <a href="./int.html" class="identifier">int_</a><-1> > c1; typedef complex< <a href="./int.html" class="identifier">int_</a><-5>, <a href="./int.html" class="identifier">int_</a><1> > c2; typedef <a href="./plus.html" class="identifier">plus</a><c1,c2> r1; <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( real<r1>::value, ==, 0 ); <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( imag<r1>::value, ==, 0 ); typedef <a href="./plus.html" class="identifier">plus</a><c1,c1> r2; <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( real<r2>::value, ==, 10 ); <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( imag<r2>::value, ==, -2 ); typedef <a href="./plus.html" class="identifier">plus</a><c2,c2> r3; <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( real<r3>::value, ==, -10 ); <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( imag<r3>::value, ==, 2 ); </pre> </div> <div class="section" id="id851"> <h3><a class="subsection-title" href="#models" name="models">Models</a></h3> <ul class="simple"> <li><a class="reference internal" href="./plus.html">plus</a></li> <li><a class="reference internal" href="./minus.html">minus</a></li> <li><a class="reference internal" href="./times.html">times</a></li> <li><a class="reference internal" href="./divides.html">divides</a></li> </ul> </div> <div class="section" id="id852"> <h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> <p><a class="reference internal" href="./tag-dispatched-metafunction.html">Tag Dispatched Metafunction</a>, <a class="reference internal" href="./metafunctions.html">Metafunctions</a>, <a class="reference internal" href="./numeric-cast.html">numeric_cast</a></p>  </div> </div> <div class="footer-separator"></div> <table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./tag-dispatched-metafunction.html" class="navigation-link">Prev</a> <a href="./trivial-metafunction.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./tag-dispatched-metafunction.html" class="navigation-link">Back</a> <a href="./trivial-metafunction.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./metafunctions-concepts.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> <td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at <a class="reference external" href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</div></td></tr></table></body> </html>