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17 <div class="section" id="numeric-metafunction">
18 <h1><a class="toc-backref" href="./changes-in-boost-1-32-0.html#id67" name="numeric-metafunction">Numeric Metafunction Protocol/Infrastructure</a></h1>
19 <p>The arithmetic, comparison and bitwise metafunctions are now
20 <cite>polymorphic</cite>, and can operate on a variety of numeric types,
21 including rational, fixed-point and complex numbers. They allow
22 <cite>mixed arithmetic</cite>, meaning that you can perform an operation on
23 arguments of different types, and the result will yield the
24 largest/most general of the argument types. The infrastructure
25 allows user-defined numeric types to be freely intermixed with
26 predefined library types. See
27 <a class="reference" href="http://cvs.sourceforge.net/viewcvs.py/boost/boost/libs/mpl/test/numeric_ops.cpp?view=markup" target="_top">http://cvs.sourceforge.net/viewcvs.py/boost/boost/libs/mpl/test/numeric_ops.cpp?view=markup</a>
28 for an illustrative example, and the <a class="reference" href="./reference-manual.html">reference manual</a> for
29 the formal infrastructure specification.</p>
30 <p>If you were using MPL numeric metafunctions on your own integral
31 wrapper class similar to <tt class="literal"><span class="pre">mpl::int_</span></tt>, you can plug your class
32 into the new infrastructure by extending it with the following
34 <pre class="literal-block">
35 typedef mpl::integral_c_tag tag;
38 <table border="1" class="table">
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49 <tr><td><pre class="first last literal-block">
50 template< int n > struct my_int
52 static int const value = n;
57 <td><pre class="first last literal-block">
58 template< int n > struct my_int
60 <strong>typedef mpl::integral_c_tag tag;</strong>
61 static int const value = n;
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