blob: 5b4f44729373a453bbff2ec76371c0c46a10e403 [file] [log] [blame]
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>I/O</title>
<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<link rel="home" href="../../../index.html" title="Chapter&#160;1.&#160;Fusion 2.0">
<link rel="up" href="../operator.html" title="Operator">
<link rel="prev" href="../operator.html" title="Operator">
<link rel="next" href="i_o/in.html" title="in">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%"><tr>
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td>
<td align="center"><a href="../../../../../../../index.html">Home</a></td>
<td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td>
<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
<td align="center"><a href="../../../../../../../more/index.htm">More</a></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="../operator.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../operator.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="i_o/in.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="fusion.sequence.operator.i_o"></a><a class="link" href="i_o.html" title="I/O">I/O</a>
</h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="i_o/in.html">in</a></span></dt>
<dt><span class="section"><a href="i_o/out.html">out</a></span></dt>
</dl></div>
<p>
The I/O operators: <code class="computeroutput"><span class="special">&lt;&lt;</span></code>
and <code class="computeroutput"><span class="special">&gt;&gt;</span></code> work generically
on all Fusion sequences. The global <code class="computeroutput"><span class="keyword">operator</span><span class="special">&lt;&lt;</span></code> has been overloaded for generic
output streams such that <a class="link" href="../../sequence.html" title="Sequence">Sequence</a>(s)
are output by recursively calling <code class="computeroutput"><span class="keyword">operator</span><span class="special">&lt;&lt;</span></code> for each element. Analogously,
the global <code class="computeroutput"><span class="keyword">operator</span><span class="special">&gt;&gt;</span></code>
has been overloaded to extract <a class="link" href="../../sequence.html" title="Sequence">Sequence</a>(s)
from generic input streams by recursively calling <code class="computeroutput"><span class="keyword">operator</span><span class="special">&gt;&gt;</span></code> for each element.
</p>
<p>
The default delimiter between the elements is space, and the <a class="link" href="../../sequence.html" title="Sequence">Sequence</a>
is enclosed in parenthesis. For Example:
</p>
<pre class="programlisting"><a class="link" href="../../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a><span class="special">&lt;</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">&gt;</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>
<span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">a</span><span class="special">;</span>
</pre>
<p>
outputs the <a class="link" href="../../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a>
as: (1.0 2 Howdy folks!)
</p>
<p>
The library defines three manipulators for changing the default behavior:
</p>
<div class="variablelist">
<p class="title"><b>Manipulators</b></p>
<dl>
<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>
<dd><p>
Defines the character that is output before the first element.
</p></dd>
<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>
<dd><p>
Defines the character that is output after the last element.
</p></dd>
<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>
<dd><p>
Defines the delimiter character between elements.
</p></dd>
</dl>
</div>
<p>
The argument to <code class="computeroutput"><span class="identifier">tuple_open</span></code>,
<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>,
a C-string, or a wide C-string.
</p>
<p>
Example:
</p>
<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">tuple_open</span><span class="special">(</span><span class="char">'['</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">tuple_close</span><span class="special">(</span><span class="char">']'</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">tuple_delimiter</span><span class="special">(</span><span class="string">", "</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">a</span><span class="special">;</span>
</pre>
<p>
outputs the same <a class="link" href="../../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a>, <code class="computeroutput"><span class="identifier">a</span></code>
as: [1.0, 2, Howdy folks!]
</p>
<p>
The same manipulators work with <code class="computeroutput"><span class="keyword">operator</span><span class="special">&gt;&gt;</span></code> and <code class="computeroutput"><span class="identifier">istream</span></code>
as well. Suppose the <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span></code>
stream contains the following data:
</p>
<pre class="programlisting"><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>
</pre>
<p>
The code:
</p>
<pre class="programlisting"><a class="link" href="../../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a><span class="special">&lt;</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">&gt;</span> <span class="identifier">i</span><span class="special">;</span>
<a class="link" href="../../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a><span class="special">&lt;</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">j</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span> <span class="special">&gt;&gt;</span> <span class="identifier">i</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span> <span class="special">&gt;&gt;</span> <span class="identifier">set_open</span><span class="special">(</span><span class="char">'['</span><span class="special">)</span> <span class="special">&gt;&gt;</span> <span class="identifier">set_close</span><span class="special">(</span><span class="char">']'</span><span class="special">)</span> <span class="special">&gt;&gt;</span> <span class="identifier">set_delimiter</span><span class="special">(</span><span class="char">':'</span><span class="special">);</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span> <span class="special">&gt;&gt;</span> <span class="identifier">j</span><span class="special">;</span>
</pre>
<p>
reads the data into the <a class="link" href="../../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a>(s) <code class="computeroutput"><span class="identifier">i</span></code>
and <code class="computeroutput"><span class="identifier">j</span></code>.
</p>
<p>
Note that extracting <a class="link" href="../../sequence.html" title="Sequence">Sequence</a>(s)
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
not generally work, since the streamed <a class="link" href="../../sequence.html" title="Sequence">Sequence</a>
representation may not be unambiguously parseable.
</p>
<a name="fusion.sequence.operator.i_o.header"></a><h6>
<a name="id901347"></a>
<a class="link" href="i_o.html#fusion.sequence.operator.i_o.header">Header</a>
</h6>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</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">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</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">io</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
</pre>
</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 &#169; 2001-2007 Joel de Guzman, Dan Marsden, Tobias
Schwinger<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>
<div class="spirit-nav">
<a accesskey="p" href="../operator.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../operator.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="i_o/in.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
</body>
</html>