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| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h5 class="title"> |
| <a name="spirit.karma.reference.numeric.real_number"></a><a class="link" href="real_number.html" title="Real Number Generators (float_, double_, etc.)">Real |
| Number Generators (<code class="computeroutput"><span class="identifier">float_</span></code>, |
| <code class="computeroutput"><span class="identifier">double_</span></code>, etc.)</a> |
| </h5></div></div></div> |
| <a name="spirit.karma.reference.numeric.real_number.description"></a><h6> |
| <a name="id1072755"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.description">Description</a> |
| </h6> |
| <p> |
| The <code class="computeroutput"><span class="identifier">real_generator</span></code> can |
| generate real numbers of arbitrary length and size limited by its template |
| parameter, <code class="computeroutput"><span class="identifier">Num</span></code>. The numeric |
| base type <code class="computeroutput"><span class="identifier">Num</span></code> can be |
| a user defined numeric type such as fixed_point (fixed point reals) and |
| bignum (unlimited precision numbers) if the type follows certain expression |
| requirements (for more information about the requirements, see <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.additional_requirements">below</a>). |
| </p> |
| <a name="spirit.karma.reference.numeric.real_number.header"></a><h6> |
| <a name="id1072798"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.header">Header</a> |
| </h6> |
| <pre class="programlisting"><span class="comment">// forwards to <boost/spirit/home/karma/numeric/real.hpp> |
| </span><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">karma_real</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| </pre> |
| <p> |
| Also, see <a class="link" href="../../../structure/include.html" title="Include">Include Structure</a>. |
| </p> |
| <a name="spirit.karma.reference.numeric.real_number.namespace"></a><h6> |
| <a name="id1072872"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.namespace">Namespace</a> |
| </h6> |
| <div class="informaltable"><table class="table"> |
| <colgroup><col></colgroup> |
| <thead><tr><th> |
| <p> |
| Name |
| </p> |
| </th></tr></thead> |
| <tbody> |
| <tr><td> |
| <p> |
| <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">lit</span> <span class="comment">// alias: |
| boost::spirit::karma::lit</span></code> |
| </p> |
| </td></tr> |
| <tr><td> |
| <p> |
| <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">float_</span> <span class="comment">// |
| alias: boost::spirit::karma::float_</span></code> |
| </p> |
| </td></tr> |
| <tr><td> |
| <p> |
| <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">double_</span> <span class="comment">// |
| alias: boost::spirit::karma::double_</span></code> |
| </p> |
| </td></tr> |
| <tr><td> |
| <p> |
| <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">long_double</span> <span class="comment">// |
| alias: boost::spirit::karma::long_double</span></code> |
| </p> |
| </td></tr> |
| </tbody> |
| </table></div> |
| <div class="note"><table border="0" summary="Note"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../images/note.png"></td> |
| <th align="left">Note</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| <code class="computeroutput"><span class="identifier">lit</span></code> is reused by the |
| <a class="link" href="../string.html" title="String">String Generators</a>, |
| the <a class="link" href="../char.html" title="Char">Character Generators</a>, |
| and the Numeric Generators. In general, a char generator is created |
| when you pass in a character, a string generator is created when you |
| pass in a string, and a numeric generator is created when you use a |
| numeric literal. |
| </p></td></tr> |
| </table></div> |
| <a name="spirit.karma.reference.numeric.real_number.synopsis"></a><h6> |
| <a name="id1074479"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.synopsis">Synopsis</a> |
| </h6> |
| <pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Num</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">RealPolicies</span><span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">real_generator</span><span class="special">;</span> |
| </pre> |
| <a name="spirit.karma.reference.numeric.real_number.template_parameters"></a><h6> |
| <a name="id1074546"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.template_parameters">Template |
| parameters</a> |
| </h6> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Parameter |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| <th> |
| <p> |
| Default |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Num</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| The type of the real number to generate. |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="keyword">double</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">RealPolicies</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| The policies to use while converting the real number. |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">real_policies</span><span class="special"><</span><span class="identifier">Num</span><span class="special">></span></code> |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <p> |
| For more information about the type <code class="computeroutput"><span class="identifier">RealPolicies</span></code> |
| see <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.real_number_formatting_policies">below</a>. |
| </p> |
| <a name="spirit.karma.reference.numeric.real_number.model_of"></a><h6> |
| <a name="id1074709"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.model_of">Model |
| of</a> |
| </h6> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| <a class="link" href="../generator_concepts/primitivegenerator.html" title="PrimitiveGenerator"><code class="computeroutput"><span class="identifier">PrimitiveGenerator</span></code></a> |
| </p></blockquote></div> |
| <div class="variablelist"> |
| <p class="title"><b>Notation</b></p> |
| <dl> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">num</span></code></span></dt> |
| <dd><p> |
| Numeric literal, any real number value, or a <a class="link" href="../karma_basics.html#spirit.karma.reference.karma_basics.lazy_argument">Lazy |
| Argument</a> that evaluates to a real number value of type |
| <code class="computeroutput"><span class="identifier">Num</span></code> |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">Num</span></code></span></dt> |
| <dd><p> |
| Type of <code class="computeroutput"><span class="identifier">num</span></code>: any |
| real number type |
| </p></dd> |
| </dl> |
| </div> |
| <a name="spirit.karma.reference.numeric.real_number.expression_semantics"></a><h6> |
| <a name="id1074810"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.expression_semantics">Expression |
| Semantics</a> |
| </h6> |
| <p> |
| Semantics of an expression is defined only where it differs from, or |
| is not defined in <a class="link" href="../generator_concepts/primitivegenerator.html" title="PrimitiveGenerator"><code class="computeroutput"><span class="identifier">PrimitiveGenerator</span></code></a>. |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Expression |
| </p> |
| </th> |
| <th> |
| <p> |
| Semantics |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">lit</span><span class="special">(</span><span class="identifier">num</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Generate the real number literal <code class="computeroutput"><span class="identifier">num</span></code> |
| using the default formatting (no trailing zeros, <code class="computeroutput"><span class="identifier">fixed</span></code> representation for |
| numbers <code class="computeroutput"><span class="identifier">fabs</span><span class="special">(</span><span class="identifier">n</span><span class="special">)</span> <span class="special"><=</span> |
| <span class="number">1e5</span> <span class="special">&&</span> |
| <span class="identifier">fabs</span><span class="special">(</span><span class="identifier">n</span><span class="special">)</span> |
| <span class="special">></span> <span class="number">1e-3</span></code>, |
| scientific representation otherwise, 3 fractional digits, sign |
| is only printed for negative literals). This generator never |
| fails (unless the underlying output stream reports an error). |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">float_</span> |
| <span class="identifier">double_</span> |
| <span class="identifier">long_double</span></pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| Generate the real number provided by a mandatory attribute |
| using the default formatting (no trailing zeros, <code class="computeroutput"><span class="identifier">fixed</span></code> representation for |
| numbers <code class="computeroutput"><span class="identifier">fabs</span><span class="special">(</span><span class="identifier">n</span><span class="special">)</span> <span class="special"><=</span> |
| <span class="number">1e5</span> <span class="special">&&</span> |
| <span class="identifier">fabs</span><span class="special">(</span><span class="identifier">n</span><span class="special">)</span> |
| <span class="special">></span> <span class="number">1e-3</span></code>, |
| scientific representation otherwise, 3 fractional digits, sign |
| is only printed for negative literals). This generator never |
| fails (unless the underlying output stream reports an error). |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">float_</span><span class="special">(</span><span class="identifier">num</span><span class="special">)</span> |
| <span class="identifier">double_</span><span class="special">(</span><span class="identifier">num</span><span class="special">)</span> |
| <span class="identifier">long_double</span><span class="special">(</span><span class="identifier">num</span><span class="special">)</span></pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| Generate the real point number provided by the immediate literal |
| value the generator is initialized from using the default formatting |
| (no trailing zeros, <code class="computeroutput"><span class="identifier">fixed</span></code> |
| representation for numbers <code class="computeroutput"><span class="identifier">fabs</span><span class="special">(</span><span class="identifier">n</span><span class="special">)</span> <span class="special"><=</span> |
| <span class="number">1e5</span> <span class="special">&&</span> |
| <span class="identifier">fabs</span><span class="special">(</span><span class="identifier">n</span><span class="special">)</span> |
| <span class="special">></span> <span class="number">1e-3</span></code>, |
| scientific representation otherwise, 3 fractional digits, sign |
| is only printed for negative literals). If this generator has |
| an associated attribute it succeeds only if the attribute is |
| equal to the immediate literal (unless the underlying output |
| stream reports an error). Otherwise this generator fails and |
| does not generate any output. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <p> |
| All generators listed in the table above (except <code class="computeroutput"><span class="identifier">lit</span><span class="special">(</span><span class="identifier">num</span><span class="special">)</span></code>) are predefined specializations of the |
| <code class="computeroutput"><span class="identifier">real_generator</span><span class="special"><</span><span class="identifier">Num</span><span class="special">,</span> <span class="identifier">RealPolicies</span><span class="special">></span></code> |
| basic real number generator type described below. It is possible to directly |
| use this type to create real number generators using a wide range of |
| formatting options. |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Expression |
| </p> |
| </th> |
| <th> |
| <p> |
| Semantics |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">real_generator</span><span class="special"><</span> |
| <span class="identifier">Num</span><span class="special">,</span> <span class="identifier">RealPolicies</span> |
| <span class="special">>()</span></pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| Generate the real number of type <code class="computeroutput"><span class="identifier">Num</span></code> |
| provided by a mandatory attribute using the specified <code class="computeroutput"><span class="identifier">RealPolicies</span></code>. This generator |
| never fails (unless the underlying output stream reports an |
| error). |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">real_generator</span><span class="special"><</span> |
| <span class="identifier">Num</span><span class="special">,</span> <span class="identifier">RealPolicies</span> |
| <span class="special">>()(</span><span class="identifier">num</span><span class="special">)</span></pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| Generate the real number of type <code class="computeroutput"><span class="identifier">Num</span></code> |
| provided by the immediate literal value the generator is initialized |
| from using the specified <code class="computeroutput"><span class="identifier">RealPolicies</span></code>. |
| If this generator has an associated attribute it succeeds only |
| if the attribute is equal to the immediate literal (unless |
| the underlying output stream reports an error). Otherwise this |
| generator fails and does not generate any output. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <a name="spirit.karma.reference.numeric.real_number.additional_requirements"></a><h6> |
| <a name="id1075433"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.additional_requirements">Additional |
| Requirements</a> |
| </h6> |
| <p> |
| The following list enumerates the requirements which must be met in order |
| to use a certain type <code class="computeroutput"><span class="identifier">Num</span></code> |
| to instantiate a <code class="computeroutput"><span class="identifier">real_generator</span><span class="special"><</span><span class="identifier">Num</span><span class="special">,</span> <span class="identifier">Policies</span><span class="special">></span></code>. |
| </p> |
| <p> |
| In order to be usable as the first template parameter for <code class="computeroutput"><span class="identifier">real_generator</span><span class="special"><></span></code> |
| the type <code class="computeroutput"><span class="identifier">Num</span></code> must have |
| defined: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"> |
| comparison operators for: <code class="computeroutput"><span class="special"><</span></code>, |
| <code class="computeroutput"><span class="special"><=</span></code>, <code class="computeroutput"><span class="special">==</span></code>, <code class="computeroutput"><span class="special">!=</span></code>, |
| <code class="computeroutput"><span class="special">></span></code>, and <code class="computeroutput"><span class="special">>=</span></code> |
| </li> |
| <li class="listitem"> |
| numeric operators for: <code class="computeroutput"><span class="special">+</span></code>, |
| <code class="computeroutput"><span class="special">-</span></code>, <code class="computeroutput"><span class="special">/</span></code>, |
| <code class="computeroutput"><span class="special">*</span></code>, and <code class="computeroutput"><span class="special">%</span></code> |
| </li> |
| <li class="listitem"> |
| functions implementing the interface and the semantics of: <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">fmod</span></code>, <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pow</span></code>, |
| <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">log10</span></code>, <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">lround</span></code>, |
| <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">ltrunc</span></code>, <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">modf</span></code>, |
| <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">floor</span></code>, and <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">ceil</span></code>. |
| These need to be defined in a way so that they will be found using |
| argument dependent lookup (ADL). |
| </li> |
| <li class="listitem"> |
| a valid specialization of the type <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special"><</span><span class="identifier">Num</span><span class="special">></span></code> allowing for numeric property |
| inspection. |
| </li> |
| </ul></div> |
| <a name="spirit.karma.reference.numeric.real_number.attributes"></a><h6> |
| <a name="id1075757"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.attributes">Attributes</a> |
| </h6> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Expression |
| </p> |
| </th> |
| <th> |
| <p> |
| Attribute |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">lit</span><span class="special">(</span><span class="identifier">num</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">unused</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">float_</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="keyword">float</span></code>, attribute |
| is mandatory (otherwise compilation will fail) |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">float_</span><span class="special">(</span><span class="identifier">num</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">float_</span></code>, attribute |
| is optional, if it is supplied, the generator compares the |
| attribute with <code class="computeroutput"><span class="identifier">num</span></code> |
| and succeeds only if both are equal, failing otherwise. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">double_</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="keyword">double</span></code>, attribute |
| is mandatory (otherwise compilation will fail) |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">double_</span><span class="special">(</span><span class="identifier">num</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="keyword">double</span></code>, attribute |
| is optional, if it is supplied, the generator compares the |
| attribute with <code class="computeroutput"><span class="identifier">num</span></code> |
| and succeeds only if both are equal, failing otherwise. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">long_double</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="keyword">long</span> <span class="keyword">double</span></code>, |
| attribute is mandatory (otherwise compilation will fail) |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">long_double</span><span class="special">(</span><span class="identifier">num</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="keyword">long</span> <span class="keyword">double</span></code>, |
| attribute is optional, if it is supplied, the generator compares |
| the attribute with <code class="computeroutput"><span class="identifier">num</span></code> |
| and succeeds only if both are equal, failing otherwise. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">real_generator</span><span class="special"><</span> |
| <span class="identifier">Num</span><span class="special">,</span> <span class="identifier">Policies</span> |
| <span class="special">>()</span></pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Num</span></code>, attribute |
| is mandatory (otherwise compilation will fail) |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">real_generator</span><span class="special"><</span> |
| <span class="identifier">Num</span><span class="special">,</span> <span class="identifier">Policies</span> |
| <span class="special">>()(</span><span class="identifier">num</span><span class="special">)</span></pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Num</span></code>, attribute |
| is optional, if it is supplied, the generator compares the |
| attribute with <code class="computeroutput"><span class="identifier">num</span></code> |
| and succeeds only if both are equal, failing otherwise. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <div class="note"><table border="0" summary="Note"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../images/note.png"></td> |
| <th align="left">Note</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| In addition to their usual attribute of type <code class="computeroutput"><span class="identifier">Num</span></code> |
| all listed generators accept an instance of a <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span><span class="special"><</span><span class="identifier">Num</span><span class="special">></span></code> as well. If the <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span><span class="special"><></span></code> is initialized (holds a value) |
| the generators behave as if their attribute was an instance of <code class="computeroutput"><span class="identifier">Num</span></code> and emit the value stored in |
| the <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span><span class="special"><></span></code>. |
| Otherwise the generators will fail. |
| </p></td></tr> |
| </table></div> |
| <a name="spirit.karma.reference.numeric.real_number.real_number_formatting_policies"></a><h6> |
| <a name="id1076313"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.real_number_formatting_policies">Real |
| Number Formatting Policies</a> |
| </h6> |
| <p> |
| If special formatting of a real number is needed, overload the policy |
| class <code class="computeroutput"><span class="identifier">real_policies</span><span class="special"><</span><span class="identifier">Num</span><span class="special">></span></code> |
| and use it as a template parameter to the <code class="computeroutput"><span class="identifier">real_generator</span><span class="special"><></span></code> real number generator. For instance: |
| </p> |
| <pre class="programlisting"><span class="comment">// define a new real number formatting policy |
| </span><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Num</span><span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">scientific_policy</span> <span class="special">:</span> <span class="identifier">real_policies</span><span class="special"><</span><span class="identifier">Num</span><span class="special">></span> |
| <span class="special">{</span> |
| <span class="comment">// we want the numbers always to be in scientific format |
| </span> <span class="keyword">static</span> <span class="keyword">int</span> <span class="identifier">floatfield</span><span class="special">(</span><span class="identifier">Num</span> <span class="identifier">n</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">fmtflags</span><span class="special">::</span><span class="identifier">scientific</span><span class="special">;</span> <span class="special">}</span> |
| <span class="special">};</span> |
| |
| <span class="comment">// define a new generator type based on the new policy |
| </span><span class="keyword">typedef</span> <span class="identifier">real_generator</span><span class="special"><</span><span class="keyword">double</span><span class="special">,</span> <span class="identifier">scientific_policy</span><span class="special"><</span><span class="keyword">double</span><span class="special">></span> <span class="special">></span> <span class="identifier">science_type</span><span class="special">;</span> |
| <span class="identifier">science_type</span> <span class="keyword">const</span> <span class="identifier">scientific</span> <span class="special">=</span> <span class="identifier">science_type</span><span class="special">();</span> |
| |
| <span class="comment">// use the new generator |
| </span><span class="identifier">generate</span><span class="special">(</span><span class="identifier">sink</span><span class="special">,</span> <span class="identifier">science_type</span><span class="special">(),</span> <span class="number">1.0</span><span class="special">);</span> <span class="comment">// will output: 1.0e00 |
| </span><span class="identifier">generate</span><span class="special">(</span><span class="identifier">sink</span><span class="special">,</span> <span class="identifier">scientific</span><span class="special">,</span> <span class="number">0.1</span><span class="special">);</span> <span class="comment">// will output: 1.0e-01 |
| </span></pre> |
| <p> |
| The template parameter <code class="computeroutput"><span class="identifier">Num</span></code> |
| should be the type to be formatted using the overloaded policy type. |
| At the same time <code class="computeroutput"><span class="identifier">Num</span></code> |
| will be used as the attribute type of the created real number generator. |
| </p> |
| <a name="spirit.karma.reference.numeric.real_number.real_number_formatting_policy_expression_semantics"></a><h6> |
| <a name="id1077370"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.real_number_formatting_policy_expression_semantics">Real |
| Number Formatting Policy Expression Semantics</a> |
| </h6> |
| <p> |
| A real number formatting policy should expose the following variables |
| and functions: |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Expression |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Inserter</span> |
| <span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">OutputIterator</span> |
| <span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Policies</span><span class="special">></span> |
| <span class="keyword">bool</span> <span class="identifier">call</span> <span class="special">(</span><span class="identifier">OutputIterator</span><span class="special">&</span> <span class="identifier">sink</span><span class="special">,</span> <span class="identifier">Num</span> <span class="identifier">n</span> |
| <span class="special">,</span> <span class="identifier">Policies</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">p</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| This is the main function used to generate the output for a |
| real number. It is called by the real generator in order to |
| perform the conversion. In theory all of the work can be implemented |
| here, but the easiest way is to use existing functionality |
| provided by the type specified by the template parameter <code class="computeroutput"><span class="identifier">Inserter</span></code>. The default implementation |
| of this functions is: |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Inserter</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">OutputIterator</span> |
| <span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Policies</span><span class="special">></span> |
| <span class="keyword">static</span> <span class="keyword">bool</span> |
| <span class="identifier">call</span> <span class="special">(</span><span class="identifier">OutputIterator</span><span class="special">&</span> <span class="identifier">sink</span><span class="special">,</span> <span class="identifier">Num</span> <span class="identifier">n</span><span class="special">,</span> <span class="identifier">Policies</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">p</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="keyword">return</span> <span class="identifier">Inserter</span><span class="special">::</span><span class="identifier">call_n</span><span class="special">(</span><span class="identifier">sink</span><span class="special">,</span> <span class="identifier">n</span><span class="special">,</span> <span class="identifier">p</span><span class="special">);</span> |
| <span class="special">}</span> |
| </pre> |
| <p> |
| <code class="computeroutput"><span class="identifier">sink</span></code> is the |
| output iterator to use for generation |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">n</span></code> is the real |
| number to convert |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">p</span></code> is the instance |
| of the policy type used to instantiate this real number generator. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">bool</span> <span class="identifier">force_sign</span><span class="special">(</span><span class="identifier">Num</span> <span class="identifier">n</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| The default behavior is to not to require generating a sign. |
| If the function <code class="computeroutput"><span class="identifier">force_sign</span><span class="special">()</span></code> returns true, then all generated |
| numbers will have a sign (<code class="computeroutput"><span class="char">'+'</span></code> |
| or <code class="computeroutput"><span class="char">'-'</span></code>, zeros will |
| have a space instead of a sign). |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">n</span></code> is the real |
| number to output. This can be used to adjust the required behavior |
| depending on the value of this number. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">bool</span> <span class="identifier">trailing_zeros</span><span class="special">(</span><span class="identifier">Num</span> <span class="identifier">n</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| Return whether trailing zero digits have to be emitted in the |
| fractional part of the output. If set, this flag instructs |
| the real number generator to emit trailing zeros up to the |
| required precision digits (as returned by the <code class="computeroutput"><span class="identifier">precision</span><span class="special">()</span></code> |
| function). |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">n</span></code> is the real |
| number to output. This can be used to adjust the required behavior |
| depending on the value of this number. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">int</span> <span class="identifier">floatfield</span><span class="special">(</span><span class="identifier">Num</span> <span class="identifier">n</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| Decide, which representation type to use in the generated output. |
| </p> |
| <p> |
| By default all numbers having an absolute value of zero or |
| in between <code class="computeroutput"><span class="number">0.001</span></code> |
| and <code class="computeroutput"><span class="number">100000</span></code> will |
| be generated using the fixed format, all others will be generated |
| using the scientific representation. |
| </p> |
| <p> |
| The <code class="computeroutput"><span class="identifier">trailing_zeros</span><span class="special">()</span></code> can be used to force the |
| output of trailing zeros in the fractional part up to the number |
| of digits returned by the <code class="computeroutput"><span class="identifier">precision</span><span class="special">()</span></code> member function. The default |
| is not to generate the trailing zeros. |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">n</span></code> is the real |
| number to output. This can be used to adjust the formatting |
| flags depending on the value of this number. |
| </p> |
| <p> |
| The return value has to be either <code class="computeroutput"><span class="identifier">fmtflags</span><span class="special">::</span><span class="identifier">scientific</span></code> |
| (generate real number values in scientific notation) or <code class="computeroutput"><span class="identifier">fmtflags</span><span class="special">::</span><span class="identifier">fixed</span></code> (generate real number |
| values in fixed-point notation). |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">unsigned</span> <span class="identifier">precision</span><span class="special">(</span><span class="identifier">Num</span> <span class="identifier">n</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| Return the maximum number of decimal digits to generate in |
| the fractional part of the output. |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">n</span></code> is the real |
| number to output. This can be used to adjust the required precision |
| depending on the value of this number. If the trailing zeros |
| flag is specified the fractional part of the output will be |
| 'filled' with zeros, if appropriate. |
| </p> |
| <p> |
| <span class="bold"><strong>Note:</strong></span> If the trailing_zeros |
| flag is not in effect additional semantics apply. See the description |
| for the <code class="computeroutput"><span class="identifier">fraction_part</span><span class="special">()</span></code> function below. Moreover, |
| this precision will be limited to the value of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">digits10</span> <span class="special">+</span> |
| <span class="number">1</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">bool</span> <span class="identifier">ForceSign</span><span class="special">,</span> |
| <span class="keyword">typename</span> <span class="identifier">OutputIterator</span><span class="special">></span> |
| <span class="keyword">bool</span> <span class="identifier">integer_part</span><span class="special">(</span><span class="identifier">OutputIterator</span><span class="special">&</span> <span class="identifier">sink</span> |
| <span class="special">,</span> <span class="identifier">Num</span> <span class="identifier">n</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">sign</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">force_sign</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| This function is called to generate the integer part of the |
| real number. |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">sink</span></code> is the |
| output iterator to use for generation |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">n</span></code> is the absolute |
| value of the integer part of the real number to convert (always |
| non-negative) |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">sign</span></code> is the |
| sign of the overall real number to convert. |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">force_sign</span></code> |
| is a flag indicating whether a sign has to be generated even |
| for non-negative numbers (this is the same as has been returned |
| from the function <code class="computeroutput"><span class="identifier">force_sign</span><span class="special">()</span></code> described above) |
| </p> |
| <p> |
| The return value defines the outcome of the whole generator. |
| If it is <code class="computeroutput"><span class="keyword">false</span></code>, |
| no further output is generated, immediately returning <code class="computeroutput"><span class="keyword">false</span></code> from the calling <code class="computeroutput"><span class="identifier">real_generator</span></code> as well. If |
| it is <code class="computeroutput"><span class="keyword">true</span></code>, normal |
| output generation continues. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">OutputIterator</span><span class="special">></span> |
| <span class="keyword">bool</span> <span class="identifier">dot</span><span class="special">(</span><span class="identifier">OutputIterator</span><span class="special">&</span> <span class="identifier">sink</span><span class="special">,</span> <span class="identifier">Num</span> <span class="identifier">n</span><span class="special">,</span> |
| <span class="keyword">unsigned</span> <span class="identifier">precision</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| This function is called to generate the decimal point. |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">sink</span></code> is the |
| output iterator to use for generation |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">n</span></code> is the fractional |
| part of the real number to convert. Note that this number is |
| scaled such, that it represents the number of units which correspond |
| to the value returned from the <code class="computeroutput"><span class="identifier">precision</span><span class="special">()</span></code> function earlier. I.e. a |
| fractional part of <code class="computeroutput"><span class="number">0.01234</span></code> |
| is represented as <code class="computeroutput"><span class="number">1234</span></code> |
| when the function <code class="computeroutput"><span class="identifier">precision</span><span class="special">()</span></code> returned <code class="computeroutput"><span class="number">5</span></code>. |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">precision</span></code> is |
| the number of digits to emit as returned by the function <code class="computeroutput"><span class="identifier">precision</span><span class="special">()</span></code> |
| described above |
| </p> |
| <p> |
| This is given to allow to decide, whether a decimal point has |
| to be generated at all. |
| </p> |
| <p> |
| <span class="bold"><strong>Note:</strong></span> If the <code class="computeroutput"><span class="identifier">trailing_zeros</span></code> flag is not |
| in effect additional comments apply. See the description for |
| the <code class="computeroutput"><span class="identifier">fraction_part</span><span class="special">()</span></code> function below. |
| </p> |
| <p> |
| The return value defines the outcome of the whole generator. |
| If it is <code class="computeroutput"><span class="keyword">false</span></code>, |
| no further output is generated, immediately returning <code class="computeroutput"><span class="keyword">false</span></code> from the calling <code class="computeroutput"><span class="identifier">real_generator</span></code> as well. If |
| it is <code class="computeroutput"><span class="keyword">true</span></code>, normal |
| output generation continues. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">OutputIterator</span><span class="special">></span> |
| <span class="keyword">bool</span> <span class="identifier">fraction_part</span><span class="special">(</span><span class="identifier">OutputIterator</span><span class="special">&</span> <span class="identifier">sink</span><span class="special">,</span> <span class="identifier">Num</span> <span class="identifier">n</span> |
| <span class="special">,</span> <span class="keyword">unsigned</span> <span class="identifier">adjprec</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="identifier">precision</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| This function is called to generate the fractional part of |
| the number. |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">sink</span></code> is the |
| output iterator to use for generation |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">n</span></code> is the fractional |
| part of the real number to convert. Note that this number is |
| scaled such, that it represents the number of units which correspond |
| to the value returned from the <code class="computeroutput"><span class="identifier">precision</span><span class="special">()</span></code> function earlier. I.e. a |
| fractional part of <code class="computeroutput"><span class="number">0.01234</span></code> |
| is represented as <code class="computeroutput"><span class="number">1234</span></code> |
| when the function <code class="computeroutput"><span class="identifier">precision</span><span class="special">()</span></code> returned <code class="computeroutput"><span class="number">5</span></code>. |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">adjprec</span></code> is |
| the corrected number of digits to emit (see note below) |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">precision</span></code> is |
| the number of digits to emit as returned by the function <code class="computeroutput"><span class="identifier">precision</span><span class="special">()</span></code> |
| described above |
| </p> |
| <p> |
| <span class="bold"><strong>Note:</strong></span> If <code class="computeroutput"><span class="identifier">trailing_zeros</span><span class="special">()</span></code> returns <code class="computeroutput"><span class="keyword">false</span></code> |
| the <code class="computeroutput"><span class="identifier">adjprec</span></code> |
| parameter will have been corrected from the value the <code class="computeroutput"><span class="identifier">precision</span><span class="special">()</span></code> |
| function returned earlier (defining the maximal number of fractional |
| digits) in the sense, that it takes into account trailing zeros. |
| I.e. a real number <code class="computeroutput"><span class="number">0.0123</span></code> |
| and a value of <code class="computeroutput"><span class="number">5</span></code> |
| returned from <code class="computeroutput"><span class="identifier">precision</span><span class="special">()</span></code> will result in: |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">trailing_zeros</span><span class="special">()</span></code> returned <code class="computeroutput"><span class="keyword">false</span></code>: |
| <code class="computeroutput"><span class="identifier">n</span></code> will be |
| <code class="computeroutput"><span class="number">123</span></code>, and <code class="computeroutput"><span class="identifier">adjprec</span></code> will be <code class="computeroutput"><span class="number">4</span></code> (as we need to print <code class="computeroutput"><span class="number">0123</span></code>) |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">trailing_zeros</span><span class="special">()</span></code> returned <code class="computeroutput"><span class="keyword">true</span></code>: |
| <code class="computeroutput"><span class="identifier">n</span></code> will be |
| <code class="computeroutput"><span class="number">1230</span></code>, and <code class="computeroutput"><span class="identifier">adjprec</span></code> will be <code class="computeroutput"><span class="number">5</span></code> (as we need to print <code class="computeroutput"><span class="number">01230</span></code>) |
| </p> |
| <p> |
| The missing preceding zeros in the fractional part have to |
| be supplied by the implementation of this policy function. |
| </p> |
| <p> |
| The return value defines the outcome of the whole generator. |
| If it is <code class="computeroutput"><span class="keyword">false</span></code>, |
| no further output is generated, immediately returning <code class="computeroutput"><span class="keyword">false</span></code> from the calling <code class="computeroutput"><span class="identifier">real_generator</span></code> as well. If |
| it is <code class="computeroutput"><span class="keyword">true</span></code>, normal |
| output generation continues. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">CharEncoding</span><span class="special">,</span> |
| <span class="keyword">typename</span> <span class="identifier">Tag</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">OutputIterator</span><span class="special">></span> |
| <span class="keyword">bool</span> <span class="identifier">exponent</span><span class="special">(</span> |
| <span class="identifier">OutputIterator</span><span class="special">&</span> <span class="identifier">sink</span><span class="special">,</span> <span class="keyword">long</span> <span class="identifier">n</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| This function is called to generate the exponential part of |
| the number (this is called only if the <code class="computeroutput"><span class="identifier">floatfield</span><span class="special">()</span></code> function returned the <code class="computeroutput"><span class="identifier">fmtflags</span><span class="special">::</span><span class="identifier">scientific</span></code> flag). |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">sink</span></code> is the |
| output iterator to use for generation |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">n</span></code> is the (signed) |
| exponential part of the real number to convert. |
| </p> |
| <p> |
| The template parameters <code class="computeroutput"><span class="identifier">CharEncoding</span></code> |
| and <code class="computeroutput"><span class="identifier">Tag</span></code> are |
| either of the type <code class="computeroutput"><span class="identifier">unused_type</span></code> |
| or describe the character class and conversion to be applied |
| to any output possibly influenced by either the <code class="computeroutput"><span class="identifier">lower</span><span class="special">[]</span></code> |
| or <code class="computeroutput"><span class="identifier">upper</span><span class="special">[]</span></code> |
| directives. |
| </p> |
| <p> |
| The return value defines the outcome of the whole generator. |
| If it is <code class="computeroutput"><span class="keyword">false</span></code>, |
| no further output is generated, immediately returning <code class="computeroutput"><span class="keyword">false</span></code> from the calling <code class="computeroutput"><span class="identifier">real_generator</span></code> as well. If |
| it is <code class="computeroutput"><span class="keyword">true</span></code>, normal |
| output generation continues. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">CharEncoding</span> |
| <span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Tag</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">OutputIterator</span><span class="special">></span> |
| <span class="keyword">bool</span> <span class="identifier">nan</span> <span class="special">(</span><span class="identifier">OutputIterator</span><span class="special">&</span> <span class="identifier">sink</span><span class="special">,</span> <span class="identifier">Num</span> <span class="identifier">n</span> |
| <span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">force_sign</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| This function is called whenever the number to print is a non-normal |
| real number of type <code class="computeroutput"><span class="identifier">NaN</span></code>. |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">sink</span></code> is the |
| output iterator to use for generation |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">n</span></code> is the (signed) |
| real number to convert |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">force_sign</span></code> |
| is a flag indicating whether a sign has to be generated even |
| for non-negative numbers (this is the same as has been returned |
| from the function <code class="computeroutput"><span class="identifier">force_sign</span><span class="special">()</span></code> described above) |
| </p> |
| <p> |
| The template parameters <code class="computeroutput"><span class="identifier">CharEncoding</span></code> |
| and <code class="computeroutput"><span class="identifier">Tag</span></code> are |
| either of the type <code class="computeroutput"><span class="identifier">unused_type</span></code> |
| or describe the character class and conversion to be applied |
| to any output possibly influenced by either the <code class="computeroutput"><span class="identifier">lower</span><span class="special">[]</span></code> |
| or <code class="computeroutput"><span class="identifier">upper</span><span class="special">[]</span></code> |
| directives. |
| </p> |
| <p> |
| The return value defines the outcome of the whole generator. |
| If it is <code class="computeroutput"><span class="keyword">false</span></code>, |
| no further output is generated, immediately returning <code class="computeroutput"><span class="keyword">false</span></code> from the calling <code class="computeroutput"><span class="identifier">real_generator</span></code> as well. If |
| it is <code class="computeroutput"><span class="keyword">true</span></code>, normal |
| output generation continues. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">CharEncoding</span> |
| <span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Tag</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">OutputIterator</span><span class="special">></span> |
| <span class="keyword">bool</span> <span class="identifier">inf</span> <span class="special">(</span><span class="identifier">OutputIterator</span><span class="special">&</span> <span class="identifier">sink</span><span class="special">,</span> <span class="identifier">Num</span> <span class="identifier">n</span> |
| <span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">force_sign</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| This function is called whenever the number to print is a non-normal |
| real number of type <code class="computeroutput"><span class="identifier">Inf</span></code>. |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">sink</span></code> is the |
| output iterator to use for generation |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">n</span></code> is the (signed) |
| real number to convert |
| </p> |
| <p> |
| <code class="computeroutput"><span class="identifier">force_sign</span></code> |
| is a flag indicating whether a sign has to be generated even |
| for non-negative numbers (this is the same as has been returned |
| from the function <code class="computeroutput"><span class="identifier">force_sign</span><span class="special">()</span></code> described above) |
| </p> |
| <p> |
| The template parameters <code class="computeroutput"><span class="identifier">CharEncoding</span></code> |
| and <code class="computeroutput"><span class="identifier">Tag</span></code> are |
| either of the type <code class="computeroutput"><span class="identifier">unused_type</span></code> |
| or describe the character class and conversion to be applied |
| to any output possibly influenced by either the <code class="computeroutput"><span class="identifier">lower</span><span class="special">[]</span></code> |
| or <code class="computeroutput"><span class="identifier">upper</span><span class="special">[]</span></code> |
| directives. |
| </p> |
| <p> |
| The return value defines the outcome of the whole generator. |
| If it is <code class="computeroutput"><span class="keyword">false</span></code>, |
| no further output is generated, immediately returning <code class="computeroutput"><span class="keyword">false</span></code> from the calling <code class="computeroutput"><span class="identifier">real_generator</span></code> as well. If |
| it is <code class="computeroutput"><span class="keyword">true</span></code>, normal |
| output generation continues. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <div class="tip"><table border="0" summary="Tip"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Tip]" src="../../../../images/tip.png"></td> |
| <th align="left">Tip</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| The easiest way to implement a proper real number formatting policy |
| is to derive a new type from the the type <code class="computeroutput"><span class="identifier">real_policies</span><span class="special"><></span></code> while overriding the aspects |
| of the formatting which need to be changed. |
| </p></td></tr> |
| </table></div> |
| <a name="spirit.karma.reference.numeric.real_number.complexity"></a><h6> |
| <a name="id1080946"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.complexity">Complexity</a> |
| </h6> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| O(N), where <code class="computeroutput"><span class="identifier">N</span></code> is the |
| number of digits needed to represent the generated real number. |
| </p></blockquote></div> |
| <a name="spirit.karma.reference.numeric.real_number.example"></a><h6> |
| <a name="id1080973"></a> |
| <a class="link" href="real_number.html#spirit.karma.reference.numeric.real_number.example">Example</a> |
| </h6> |
| <div class="note"><table border="0" summary="Note"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../images/note.png"></td> |
| <th align="left">Note</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| The test harness for the example(s) below is presented in the <a class="link" href="../karma_basics.html#spirit.karma.reference.karma_basics.examples">Basics Examples</a> |
| section. |
| </p></td></tr> |
| </table></div> |
| <p> |
| Some includes: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">karma</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">phoenix_core</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">phoenix_operator</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">std_pair</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">string</span><span class="special">></span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| Some using declarations: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">karma</span><span class="special">::</span><span class="identifier">double_</span><span class="special">;</span> |
| <span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">karma</span><span class="special">::</span><span class="identifier">lit</span><span class="special">;</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| Basic usage of an <code class="computeroutput"><span class="identifier">double_</span></code> |
| generator: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">test_generator</span><span class="special">(</span><span class="string">"2.0"</span><span class="special">,</span> <span class="identifier">lit</span><span class="special">(</span><span class="number">2.0</span><span class="special">));</span> |
| <span class="identifier">test_generator</span><span class="special">(</span><span class="string">"2.0"</span><span class="special">,</span> <span class="identifier">double_</span><span class="special">(</span><span class="number">2</span><span class="special">));</span> |
| <span class="identifier">test_generator_attr</span><span class="special">(</span><span class="string">"2.0"</span><span class="special">,</span> <span class="identifier">double_</span><span class="special">(</span><span class="number">2.0</span><span class="special">),</span> <span class="number">2.0</span><span class="special">);</span> |
| <span class="identifier">test_generator_attr</span><span class="special">(</span><span class="string">""</span><span class="special">,</span> <span class="identifier">double_</span><span class="special">(</span><span class="number">2.0</span><span class="special">),</span> <span class="number">3.0</span><span class="special">);</span> <span class="comment">// fails (as 2.0 != 3.0)! |
| </span><span class="identifier">test_generator_attr</span><span class="special">(</span><span class="string">"-2.0"</span><span class="special">,</span> <span class="identifier">double_</span><span class="special">,</span> <span class="special">-</span><span class="number">2.0</span><span class="special">);</span> |
| |
| <span class="identifier">test_generator_attr</span><span class="special">(</span><span class="string">"1.234e05"</span><span class="special">,</span> <span class="identifier">double_</span><span class="special">,</span> <span class="number">1234.0e2</span><span class="special">);</span> |
| <span class="identifier">test_generator_attr</span><span class="special">(</span><span class="string">"1.234e-06"</span><span class="special">,</span> <span class="identifier">double_</span><span class="special">,</span> <span class="number">0.000001234</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2001-2010 Joel de Guzman, Hartmut Kaiser<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) |
| </p> |
| </div></td> |
| </tr></table> |
| <hr> |
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