| <?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: Reversible Algorithm</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="./inserter.html" class="navigation-link">Prev</a> <a href="./inserters.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./inserter.html" class="navigation-link">Back</a> Along</span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./algorithms-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="./algorithms.html" class="navigation-link">Algorithms</a> / <a href="./algorithms-concepts.html" class="navigation-link">Concepts</a> / <a href="./reversible-algorithm.html" class="navigation-link">Reversible Algorithm</a></td> |
| </tr></table><div class="header-separator"></div> |
| <div class="section" id="reversible-algorithm"> |
| <h1><a class="toc-backref" href="./algorithms-concepts.html#id1463">Reversible Algorithm</a></h1> |
| <div class="section" id="id459"> |
| <h3><a class="subsection-title" href="#description" name="description">Description</a></h3> |
| <p>A <a class="reference internal" href="./reversible-algorithm.html">Reversible Algorithm</a> is a member of a pair of |
| transformation algorithms that iterate over their input sequence(s) |
| in opposite directions. For each reversible |
| algorithm <tt class="literal"><span class="pre">x</span></tt> there exists a <em>counterpart</em> algorithm <tt class="literal"><span class="pre">reverse_x</span></tt>, |
| that exhibits the exact semantics of <tt class="literal"><span class="pre">x</span></tt> except that the elements |
| of its input sequence argument(s) are processed in the reverse |
| order.</p> |
| </div> |
| <div class="section" id="id460"> |
| <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">x</span></tt> is a placeholder token for the actual |
| <a class="reference internal" href="./reversible-algorithm.html">Reversible Algorithm</a>'s name, <em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub> are |
| <a class="reference internal" href="./forward-sequence.html">Forward Sequence</a>s, and <tt class="literal"><span class="pre">in</span></tt> is an <a class="reference internal" href="./inserter.html">Inserter</a>.</p> |
| <table border="1" class="docutils table"> |
| <colgroup> |
| <col width="48%" /> |
| <col width="28%" /> |
| <col width="23%" /> |
| </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">x<</span></tt><em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>, ...<tt class="literal"><span class="pre">>::type</span></tt></td> |
| <td><a class="reference internal" href="./forward-sequence.html">Forward Sequence</a></td> |
| <td>Unspecified.</td> |
| </tr> |
| <tr><td><tt class="literal"><span class="pre">x<</span></tt><em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>, ... <tt class="literal"><span class="pre">in>::type</span></tt></td> |
| <td>Any type</td> |
| <td>Unspecified.</td> |
| </tr> |
| <tr><td><tt class="literal"><span class="pre">reverse_x<</span></tt><em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>, ...<tt class="literal"><span class="pre">>::type</span></tt></td> |
| <td><a class="reference internal" href="./forward-sequence.html">Forward Sequence</a></td> |
| <td>Unspecified.</td> |
| </tr> |
| <tr><td><tt class="literal"><span class="pre">reverse_x<</span></tt><em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>, ... <tt class="literal"><span class="pre">in>::type</span></tt></td> |
| <td>Any type</td> |
| <td>Unspecified.</td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| <div class="section" id="id461"> |
| <h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> |
| <pre class="literal-block"> |
| typedef x<<em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>,...>::type t; |
| </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">Precondition:</th><td class="field-body"><p class="first"><em>s</em><sub>1</sub> is an <a class="reference internal" href="./extensible-sequence.html">Extensible Sequence</a>.</p> |
| </td> |
| </tr> |
| <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first"><tt class="literal"><span class="pre">t</span></tt> is equivalent to</p> |
| <pre class="literal-block"> |
| x< |
| <em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>,... |
| , <a href="./back-inserter.html" class="identifier">back_inserter</a>< <a href="./clear.html" class="identifier">clear</a><<em>s</em><sub>1</sub>>::type > |
| >::type |
| </pre> |
| <p>if <tt class="literal"><span class="pre">has_push_back<</span></tt><em>s</em><sub>1</sub><tt class="literal"><span class="pre">>::value</span> <span class="pre">==</span> <span class="pre">true</span></tt> and</p> |
| <pre class="literal-block"> |
| reverse_x< |
| <em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>,... |
| , <a href="./front-inserter.html" class="identifier">front_inserter</a>< <a href="./clear.html" class="identifier">clear</a><<em>s</em><sub>1</sub>>::type > |
| >::type |
| </pre> |
| <p class="last">otherwise.</p> |
| </td> |
| </tr> |
| </tbody> |
| </table> |
| <!-- .......................................................................... --> |
| <pre class="literal-block"> |
| typedef x<<em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>,...in>::type t; |
| </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">t</span></tt> is the result of an <tt class="literal"><span class="pre">x</span></tt> invocation with arguments |
| <em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,... <em>s</em><sub>n</sub>,...<tt class="literal"><span class="pre">in</span></tt>.</td> |
| </tr> |
| </tbody> |
| </table> |
| <!-- .......................................................................... --> |
| <pre class="literal-block"> |
| typedef reverse_x<<em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,... <em>s</em><sub>n</sub>,... >::type t; |
| </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">Precondition:</th><td class="field-body"><p class="first"><em>s</em><sub>1</sub> is an <a class="reference internal" href="./extensible-sequence.html">Extensible Sequence</a>.</p> |
| </td> |
| </tr> |
| <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first"><tt class="literal"><span class="pre">t</span></tt> is equivalent to</p> |
| <pre class="literal-block"> |
| x< |
| <em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>,... |
| , <a href="./front-inserter.html" class="identifier">front_inserter</a>< <a href="./clear.html" class="identifier">clear</a><<em>s</em><sub>1</sub>>::type > |
| >::type |
| </pre> |
| <p>if <tt class="literal"><span class="pre">has_push_front<</span></tt><em>s</em><sub>1</sub><tt class="literal"><span class="pre">>::value</span> <span class="pre">==</span> <span class="pre">true</span></tt> and</p> |
| <pre class="literal-block"> |
| reverse_x< |
| <em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>,... |
| , <a href="./back-inserter.html" class="identifier">back_inserter</a>< <a href="./clear.html" class="identifier">clear</a><<em>s</em><sub>1</sub>>::type > |
| >::type |
| </pre> |
| <p class="last">otherwise.</p> |
| </td> |
| </tr> |
| </tbody> |
| </table> |
| <!-- .......................................................................... --> |
| <pre class="literal-block"> |
| typedef reverse_x<<em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>,... in>::type t; |
| </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">t</span></tt> is the result of a <tt class="literal"><span class="pre">reverse_x</span></tt> invocation with arguments |
| <em>s</em><sub>1</sub>,<em>s</em><sub>2</sub>,...<em>s</em><sub>n</sub>,...<tt class="literal"><span class="pre">in</span></tt>.</td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| <div class="section" id="id462"> |
| <h3><a class="subsection-title" href="#example" name="example">Example</a></h3> |
| <pre class="literal-block"> |
| typedef <a href="./transform.html" class="identifier">transform</a>< |
| <a href="./range-c.html" class="identifier">range_c</a><int,0,10> |
| , <a href="./plus.html" class="identifier">plus</a><<a href="./placeholders.html" class="identifier">_1</a>,<a href="./int.html" class="identifier">int_</a><7> > |
| , <a href="./back-inserter.html" class="identifier">back_inserter</a>< vector0<> > |
| >::type r1; |
| |
| typedef <a href="./transform.html" class="identifier">transform</a>< r1, <a href="./minus.html" class="identifier">minus</a><<a href="./placeholders.html" class="identifier">_1</a>,<a href="./int.html" class="identifier">int_</a><2> > >::type r2; |
| typedef <a href="./reverse-transform.html" class="identifier">reverse_transform</a>< |
| r2 |
| , <a href="./minus.html" class="identifier">minus</a><<a href="./placeholders.html" class="identifier">_1</a>,5> |
| , <a href="./front-inserter.html" class="identifier">front_inserter</a>< vector0<> > |
| >::type r3; |
| |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( <a href="./equal.html" class="identifier">equal</a><r1, <a href="./range-c.html" class="identifier">range_c</a><int,7,17> > )); |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( <a href="./equal.html" class="identifier">equal</a><r2, <a href="./range-c.html" class="identifier">range_c</a><int,5,15> > )); |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( <a href="./equal.html" class="identifier">equal</a><r3, <a href="./range-c.html" class="identifier">range_c</a><int,0,10> > )); |
| </pre> |
| </div> |
| <div class="section" id="id463"> |
| <h3><a class="subsection-title" href="#models" name="models">Models</a></h3> |
| <ul class="simple"> |
| <li><a class="reference internal" href="./transform.html">transform</a></li> |
| <li><a class="reference internal" href="./remove.html">remove</a></li> |
| <li><a class="reference internal" href="./replace.html">replace</a></li> |
| </ul> |
| </div> |
| <div class="section" id="id464"> |
| <h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> |
| <p><a class="reference internal" href="./transformation-algorithms.html">Transformation Algorithms</a>, <a class="reference internal" href="./inserter.html">Inserter</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="./inserter.html" class="navigation-link">Prev</a> <a href="./inserters.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./inserter.html" class="navigation-link">Back</a> Along</span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./algorithms-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> |
