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<link rel="start" href="../../../index.html" title="Chapter 1. Fusion 2.0">
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<a accesskey="p" href="../operators.html"><img src="../../../images/prev.png" alt="Prev"></a><a accesskey="u" href="../operators.html"><img src="../../../images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../images/home.png" alt="Home"></a><a accesskey="n" href="i_o/in.html"><img src="../../../images/next.png" alt="Next"></a>
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<div class="section" lang="en">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="fusion.sequences.operators.i_o"></a><a href="i_o.html" title="I/O">I/O</a></h4></div></div></div>
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<div class="toc"><dl>
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<dt><span class="section"><a href="i_o/in.html">in</a></span></dt>
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<dt><span class="section"><a href="i_o/out.html">out</a></span></dt>
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</dl></div>
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<p>
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The I/O operators: <code class="computeroutput"><span class="special"><<</span></code>
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and <code class="computeroutput"><span class="special">>></span></code> work generically
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on all Fusion sequences. The global <code class="computeroutput"><span class="keyword">operator</span><span class="special"><<</span></code> has been overloaded for generic
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output streams such that <span class="underline">_sequence</span>_s
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are output by recursively calling <code class="computeroutput"><span class="keyword">operator</span><span class="special"><<</span></code> for each element. Analogously,
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the global <code class="computeroutput"><span class="keyword">operator</span><span class="special">>></span></code>
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has been overloaded to extract <span class="underline">_sequence</span>_s
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from generic input streams by recursively calling <code class="computeroutput"><span class="keyword">operator</span><span class="special">>></span></code> for each element.
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</p>
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<p>
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The default delimiter between the elements is space, and the <a href="../../sequences.html" title="Sequences">Sequence</a>
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is enclosed in parenthesis. For Example:
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</p>
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<pre class="programlisting">
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<a href="../containers/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a><span class="special"><</span><span class="keyword">float</span><span class="special">,</span> <span class="keyword">int</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">></span> <span class="identifier">a</span><span class="special">(</span><span class="number">1.0f</span><span class="special">,</span> <span class="number">2</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="string">"Howdy folks!"</span><span class="special">);</span>
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<span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">a</span><span class="special">;</span>
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</pre>
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<p>
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outputs the <a href="../containers/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a> as: (1.0 2 Howdy folks!)
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</p>
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<p>
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The library defines three manipulators for changing the default behavior:
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</p>
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<div class="variablelist">
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<p class="title"><b>Manipulators</b></p>
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<dl>
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<dt><span class="term"><code class="computeroutput"><span class="identifier">tuple_open</span><span class="special">(</span><span class="identifier">arg</span><span class="special">)</span></code></span></dt>
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<dd>
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Defines the character that is output before the first element.
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</dd>
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<dt><span class="term"><code class="computeroutput"><span class="identifier">tuple_close</span><span class="special">(</span><span class="identifier">arg</span><span class="special">)</span></code></span></dt>
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<dd>
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Defines the character that is output after the last element.
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</dd>
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<dt><span class="term"><code class="computeroutput"><span class="identifier">tuple_delimiter</span><span class="special">(</span><span class="identifier">arg</span><span class="special">)</span></code></span></dt>
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<dd>
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Defines the delimiter character between elements.
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</dd>
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</dl>
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</div>
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<p>
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The argument to <code class="computeroutput"><span class="identifier">tuple_open</span></code>,
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<code class="computeroutput"><span class="identifier">tuple_close</span></code> and <code class="computeroutput"><span class="identifier">tuple_delimiter</span></code> may be a <code class="computeroutput"><span class="keyword">char</span></code>, <code class="computeroutput"><span class="keyword">wchar_t</span></code>,
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a C-string, or a wide C-string.
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</p>
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<p>
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Example:
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</p>
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<pre class="programlisting">
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<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">tuple_open</span><span class="special">(</span><span class="char">'['</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">tuple_close</span><span class="special">(</span><span class="char">']'</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">tuple_delimiter</span><span class="special">(</span><span class="string">", "</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">a</span><span class="special">;</span>
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</pre>
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<p>
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outputs the same <a href="../containers/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a>, <code class="computeroutput"><span class="identifier">a</span></code>
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as: [1.0, 2, Howdy folks!]
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</p>
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<p>
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The same manipulators work with <code class="computeroutput"><span class="keyword">operator</span><span class="special">>></span></code> and <code class="computeroutput"><span class="identifier">istream</span></code>
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as well. Suppose the <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span></code>
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stream contains the following data:
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</p>
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<pre class="programlisting">
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<span class="special">(</span><span class="number">1</span> <span class="number">2</span> <span class="number">3</span><span class="special">)</span> <span class="special">[</span><span class="number">4</span><span class="special">:</span><span class="number">5</span><span class="special">]</span>
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</pre>
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<p>
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The code:
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</p>
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<pre class="programlisting">
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<a href="../containers/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">int</span><span class="special">,</span> <span class="keyword">int</span><span class="special">></span> <span class="identifier">i</span><span class="special">;</span>
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<a href="../containers/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">int</span><span class="special">></span> <span class="identifier">j</span><span class="special">;</span>
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<span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span> <span class="special">>></span> <span class="identifier">i</span><span class="special">;</span>
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<span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span> <span class="special">>></span> <span class="identifier">set_open</span><span class="special">(</span><span class="char">'['</span><span class="special">)</span> <span class="special">>></span> <span class="identifier">set_close</span><span class="special">(</span><span class="char">']'</span><span class="special">)</span> <span class="special">>></span> <span class="identifier">set_delimiter</span><span class="special">(</span><span class="char">':'</span><span class="special">);</span>
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<span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span> <span class="special">>></span> <span class="identifier">j</span><span class="special">;</span>
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</pre>
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<p>
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reads the data into the <span class="underline">_vector</span>_s
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<code class="computeroutput"><span class="identifier">i</span></code> and <code class="computeroutput"><span class="identifier">j</span></code>.
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</p>
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<p>
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Note that extracting <span class="underline">_sequence</span>_s
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with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code> or C-style string elements does
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not generally work, since the streamed <a href="../../sequences.html" title="Sequences">Sequence</a>
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representation may not be unambiguously parseable.
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</p>
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<a name="fusion.sequences.operators.i_o.header"></a><h5>
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<a name="id1074150"></a>
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<a href="i_o.html#fusion.sequences.operators.i_o.header">Header</a>
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</h5>
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<pre class="programlisting">
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<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">sequence</span><span class="special">/</span><span class="identifier">io</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
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</pre>
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</div>
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<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="left"></td>
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<td align="right"><small>Copyright © 2001-2005 Joel de Guzman, Dan Marsden</small></td>
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</tr></table>
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<hr>
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