preprocessor/doc/reference/repeat_8hpp.html

<a href="../index.htm"><IMG height=86
 alt="c++boost.gif (8819 bytes)"
 src="../../../../c++boost.gif"
 width=277 align=center></a>
<hr>
<!-- Generated by Doxygen -->
<center>
<a class="qindex" href="index.html">Main Page</a> &nbsp; <a class="qindex" href="files.html">File List</a> &nbsp; <a class="qindex" href="globals.html">File Members</a> &nbsp; </center>
<hr><h1>repeat.hpp File Reference</h1><a href="../../../../boost/preprocessor/repeat.hpp">Click here to see the header.</a>. 
<a href="#_details">More...</a>
<p>
<table border=0 cellpadding=0 cellspacing=0>
<tr><td colspan=2><br><h2>Defines</h2></td></tr>
<tr><td nowrap align=right valign=top>#define&nbsp;</td><td valign=bottom><a class="el" href="repeat_8hpp.html#a0">BOOST_PP_REPEAT</a>(N, M, P)</td></tr>
<tr><td>&nbsp;</td><td><font size=-1><em>Repeats the macro M(I,P) for I = 0 to N-1.</em> <a href="#a0">More...</a><em></em></font><br><br></td></tr>
<tr><td nowrap align=right valign=top>#define&nbsp;</td><td valign=bottom><a class="el" href="repeat_8hpp.html#a1">BOOST_PREPROCESSOR_REPEAT</a>(N, M, P)</td></tr>
<tr><td>&nbsp;</td><td><font size=-1><em>Obsolete.</em> <a href="#a1">More...</a><em></em></font><br><br></td></tr>
</table>
<hr><a name="_details"></a><h2>Detailed Description</h2>
<a href="../../../../boost/preprocessor/repeat.hpp">Click here to see the header.</a>.
<p>

<p>
<hr><h2>Define Documentation</h2>
<a name="a0" doxytag="repeat.hpp::BOOST_PP_REPEAT"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
  <tr>
    <td class="md">
      <table cellpadding="0" cellspacing="0" border="0">
        <tr>
          <td class="md" nowrap valign="top"> #define BOOST_PP_REPEAT</td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">N,         <tr>
          <td></td>
          <td></td>
          <td class="md" nowrap>M,         <tr>
          <td></td>
          <td></td>
          <td class="md" nowrap>P&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>&nbsp;          </td>
          <td class="md" valign="top">)&nbsp;</td>
          <td class="md" nowrap>
      </table>
    </td>
  </tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
  <tr>
    <td>
      &nbsp;
    </td>
    <td>

<p>
Repeats the macro M(I,P) for I = 0 to N-1.
<p>
In other words, expands to the sequence:
<p>
<pre><div class="fragment"><pre>
  M(0,P) M(1,P) ... M(N-1,P)
</pre></div></pre>
<p>
See BOOST_PP_LIMIT_MAG.
<p>
<h3>2D and 3D repetition</h3>

<p>
2D and 3D repetition are supported with the <a class="el" href="repeat__2nd_8hpp.html#a0">BOOST_PP_REPEAT_2ND</a>() and <a class="el" href="repeat__3rd_8hpp.html#a0">BOOST_PP_REPEAT_3RD</a>() macros. For example,
<p>
<pre><div class="fragment"><pre>
 A generalized macro for generating 2D arrays
  #define ARRAY_2D(W,H,M,P)\
    BOOST_PP_REPEAT_2ND\
    ( H\
    , ARRAY_2D_ROW\
    , (W,H,M,P)\
    )
  #define ARRAY_2D_ROW(Y,WHMP)\
    BOOST_PP_EXPAND\
    ( BOOST_PP_REPEAT\
      ( BOOST_PP_TUPLE_ELEM(4,0,WHMP)\
      , ARRAY_2D_ELEM\
      , (Y,BOOST_PP_TUPLE4_ENUM WHMP)\
      )\
    )
  #define BOOST_PP_TUPLE4_ENUM(A,B,C,D) A,B,C,D
  #define ARRAY_2D_ELEM(X,YWHMP)\
    BOOST_PP_TUPLE_ELEM(5,3,YWHMP)\
    BOOST_PP_EXPAND\
    ( ( X\
      , BOOST_PP_TUPLE_ELEM(5,0,YWHMP)\
      , BOOST_PP_TUPLE_ELEM(5,1,YWHMP)\
      , BOOST_PP_TUPLE_ELEM(5,2,YWHMP)\
      , BOOST_PP_TUPLE_ELEM(5,4,YWHMP)\
      )\
    )

 Here we use the above macro to generate something
  #define ELEM(X,Y,W,H,E) BOOST_PP_COMMA_IF(BOOST_PP_OR(X,Y)) E##_##X##_##Y

  ARRAY_2D(3,4,ELEM,elem)
</pre></div></pre>
<p>
expands to:
<p>
<pre><div class="fragment"><pre>
  elem_0_0, elem_1_0, elem_2_0,
  elem_0_1, elem_1_1, elem_2_1,
  elem_0_2, elem_1_2, elem_2_2,
  elem_0_3, elem_1_3, elem_2_3
</pre></div></pre>
<p>
Since recursive expansion of macros is not allowed by the C++ preprocessor, replacing the BOOST_PP_REPEAT_2ND above with BOOST_PP_REPEAT, would not produce the above expansion.
<p>
See <a class="el" href="for_8hpp.html#a0">BOOST_PP_FOR</a>().     </td>
  </tr>
</table>
<a name="a1" doxytag="repeat.hpp::BOOST_PREPROCESSOR_REPEAT"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
  <tr>
    <td class="md">
      <table cellpadding="0" cellspacing="0" border="0">
        <tr>
          <td class="md" nowrap valign="top"> #define BOOST_PREPROCESSOR_REPEAT</td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">N,         <tr>
          <td></td>
          <td></td>
          <td class="md" nowrap>M,         <tr>
          <td></td>
          <td></td>
          <td class="md" nowrap>P&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>&nbsp;          </td>
          <td class="md" valign="top">)&nbsp;</td>
          <td class="md" nowrap>
      </table>
    </td>
  </tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
  <tr>
    <td>
      &nbsp;
    </td>
    <td>

<p>
Obsolete.
<p>
Use <a class="el" href="repeat_8hpp.html#a0">BOOST_PP_REPEAT</a>().     </td>
  </tr>
</table>
<hr>
<p>© Copyright Housemarque Oy 2001</p>
<p>Permission to copy, use, modify, sell and distribute this document is granted 
  provided this copyright notice appears in all copies. This document is provided 
  "as is" without express or implied warranty, and with no claim as to its suitability 
  for any purpose. </p>

<p>Generated: <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan --><!--webbot bot="Timestamp" endspan i-checksum="15246" --></p>