ceph/src/boost/libs/preprocessor/doc/ref/seq_fold_left_s.html

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   2         <head>
   3                 <title>BOOST_PP_SEQ_FOLD_LEFT_s</title>
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   8                         The <b>BOOST_PP_SEQ_FOLD_LEFT_<i>s</i></b> macro folds (or accumulates) the
   9                         elements of a <i>seq</i> left-to-right.&nbsp; It reenters <b>BOOST_PP_SEQ_FOLD_LEFT</b>
  10                         with maximum efficiency.
  11                 </div>
  12                 <h4>
  13                         Usage
  14                 </h4>
  15                 <div class="code">
  16                         <b>BOOST_PP_SEQ_FOLD_LEFT_</b> ## <i>s</i>(<i>op</i>, <i>state</i>, <i>seq</i>)
  17                 </div>
  18                 <h4>
  19                         Arguments
  20                 </h4>
  21                 <dl>
  22                         <dt>s</dt>
  23                         <dd>
  24                                 The next available <b>BOOST_PP_SEQ_FOLD_LEFT</b> fold step.
  25                         </dd>
  26                         <dt>op</dt>
  27                         <dd>
  28                                 A ternary operation of the form <i>op</i>(<i>s</i>, <i>state</i>, <i>elem</i>).&nbsp;
  29                                 This macro is called for each element in <i>seq</i>--each time returning a new <i>state</i>.&nbsp;
  30                                 This operation is expanded by <b>BOOST_PP_SEQ_FOLD_LEFT</b> with the next
  31                                 available fold step, the current <i>state</i>, and the current element.
  32                         </dd>
  33                         <dt>state</dt>
  34                         <dd>
  35                                 The initial state of the fold.
  36                         </dd>
  37                         <dt>seq</dt>
  38                         <dd>
  39                                 The <i>seq</i> to be folded.
  40                         </dd>
  41                 </dl>
  42                 <h4>
  43                         Remarks
  44                 </h4>
  45                 <div>
  46                         For the <i>seq</i>, (<i>0</i>)(<i>1</i>)(<i>2</i>), this macro expands to:
  47                         <div>
  48                                 <i>op</i>(<i>s</i>, <i>op</i>(<i>s</i>, <i>op</i>(<i>s</i>, <i>state</i>, <i>0</i>),
  49                                 <i>1</i>), <i>2</i>)
  50                         </div>
  51                 </div>
  52                 <h4>
  53                         See Also
  54                 </h4>
  55                 <ul>
  56                         <li>
  57                                 <a href="seq_fold_left.html">BOOST_PP_SEQ_FOLD_LEFT</a></li>
  58                 </ul>
  59                 <h4>
  60                         Requirements
  61                 </h4>
  62                 <div>
  63                         <b>Header:</b> &nbsp;<a href="../headers/seq/fold_left.html">&lt;boost/preprocessor/seq/fold_left.hpp&gt;</a>
  64                 </div>
  65                 <h4>
  66                         Sample Code
  67                 </h4>
  68                 <div>
  69                         <pre>
  70 #include &lt;<a href="../headers/cat.html">boost/preprocessor/cat.hpp</a>&gt;
  71 #include &lt;<a href="../headers/seq/fold_left.html">boost/preprocessor/seq/fold_left.hpp</a>&gt;
  72 #include &lt;<a href="../headers/seq/seq.html">boost/preprocessor/seq/seq.hpp</a>&gt;
  73
  74 #define S1 (a)(b)(c)
  75 #define S2 (S1)(S1)(S1)
  76
  77 #define OP(s, state, x) state (<a href="seq_fold_left_s.html">BOOST_PP_SEQ_FOLD_LEFT_</a> ## s(OP_2, _, x))
  78 #define OP_2(s, state, x) <a href="cat.html">BOOST_PP_CAT</a>(state, x)
  79
  80 <a href="seq_fold_left.html">BOOST_PP_SEQ_FOLD_LEFT</a>(OP, <a href="seq_nil.html">BOOST_PP_SEQ_NIL</a>, S2)
  81 // expands to (_abc)(_abc)(_abc)
  82 </pre>
  83                 </div>
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  86                 <i>© Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i>
  87                 </br><i>© Copyright Paul Mensonides 2002</i>
  88         </div>
  89         <div style="margin-left: 0px;">
  90                 <p><small>Distributed under the Boost Software License, Version 1.0. (See
  91                 accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or
  92                 copy at <a href=
  93                 "http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p>
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