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diff --git a/libs/fusion/doc/html/fusion/notes.html b/libs/fusion/doc/html/fusion/notes.html new file mode 100755 index 0000000000..9442cae53e --- /dev/null +++ b/libs/fusion/doc/html/fusion/notes.html @@ -0,0 +1,484 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>Notes</title> +<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> +<link rel="home" href="../index.html" title="Chapter 1. Fusion 2.1"> +<link rel="up" href="../index.html" title="Chapter 1. Fusion 2.1"> +<link rel="prev" href="functional/generation/metafunctions/mk_unfused.html" title="make_unfused"> +<link rel="next" href="change_log.html" title="Change log"> +</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="functional/generation/metafunctions/mk_unfused.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="change_log.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +<div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="fusion.notes"></a><a class="link" href="notes.html" title="Notes">Notes</a> +</h2></div></div></div> +<h4> +<a name="fusion.notes.h0"></a> + <span><a name="fusion.notes.recursive_inlined_functions"></a></span><a class="link" href="notes.html#fusion.notes.recursive_inlined_functions">Recursive + Inlined Functions</a> + </h4> +<p> + An interesting peculiarity of functions like <a class="link" href="sequence/intrinsic/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a> when applied to a <a class="link" href="sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward + Sequence</a> like <a class="link" href="container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a> + is that what could have been linear runtime complexity effectively becomes + constant O(1) due to compiler optimization of C++ inlined functions, however + deeply recursive (up to a certain compiler limit of course). Compile time complexity + remains linear. + </p> +<h4> +<a name="fusion.notes.h1"></a> + <span><a name="fusion.notes.overloaded_functions"></a></span><a class="link" href="notes.html#fusion.notes.overloaded_functions">Overloaded + Functions</a> + </h4> +<p> + Associative sequences use function overloading to implement membership testing + and type associated key lookup. This amounts to constant runtime and amortized + constant compile time complexities. There is an overloaded function, <code class="computeroutput"><span class="identifier">f</span><span class="special">(</span><span class="identifier">k</span><span class="special">)</span></code>, for each key <span class="emphasis"><em>type</em></span> <code class="computeroutput"><span class="identifier">k</span></code>. The compiler chooses the appropriate function + given a key, <code class="computeroutput"><span class="identifier">k</span></code>. + </p> +<h4> +<a name="fusion.notes.h2"></a> + <span><a name="fusion.notes.tag_dispatching"></a></span><a class="link" href="notes.html#fusion.notes.tag_dispatching">Tag + Dispatching</a> + </h4> +<p> + Tag dispatching is a generic programming technique for selecting template specializations. + There are typically 3 components involved in the tag dispatching mechanism: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"> +<li class="listitem"> + A type for which an appropriate template specialization is required + </li> +<li class="listitem"> + A metafunction that associates the type with a tag type + </li> +<li class="listitem"> + A template that is specialized for the tag type + </li> +</ol></div> +<p> + For example, the fusion <code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">begin</span></code> metafunction + is implemented as follows: + </p> +<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Sequence</span><span class="special">></span> +<span class="keyword">struct</span> <span class="identifier">begin</span> +<span class="special">{</span> + <span class="keyword">typedef</span> <span class="keyword">typename</span> + <span class="identifier">result_of</span><span class="special">::</span><span class="identifier">begin_impl</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">traits</span><span class="special">::</span><span class="identifier">tag_of</span><span class="special"><</span><span class="identifier">Sequence</span><span class="special">>::</span><span class="identifier">type</span><span class="special">>::</span> + <span class="keyword">template</span> <span class="identifier">apply</span><span class="special"><</span><span class="identifier">Sequence</span><span class="special">>::</span><span class="identifier">type</span> + <span class="identifier">type</span><span class="special">;</span> +<span class="special">};</span> +</pre> +<p> + In the case: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"> +<li class="listitem"> + <code class="computeroutput"><span class="identifier">Sequence</span></code> is the type for + which a suitable implementation of <code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">begin_impl</span></code> + is required + </li> +<li class="listitem"> + <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">tag_of</span></code> is the metafunction that associates + <code class="computeroutput"><span class="identifier">Sequence</span></code> with an appropriate + tag + </li> +<li class="listitem"> + <code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">begin_impl</span></code> is the template which is specialized + to provide an implementation for each tag type + </li> +</ol></div> +<h4> +<a name="fusion.notes.h3"></a> + <span><a name="fusion.notes.extensibility"></a></span><a class="link" href="notes.html#fusion.notes.extensibility">Extensibility</a> + </h4> +<p> + Unlike <a href="http://www.boost.org/libs/mpl/index.html" target="_top">MPL</a>, there + is no extensibe sequence concept in fusion. This does not mean that Fusion + sequences are not extensible. In fact, all Fusion sequences are inherently + extensible. It is just that the manner of sequence extension in Fusion is diferent + from both <a href="http://en.wikipedia.org/wiki/Standard_Template_Library" target="_top">STL</a> + and <a href="http://www.boost.org/libs/mpl/index.html" target="_top">MPL</a> on account + of the lazy nature of fusion <a class="link" href="algorithm.html" title="Algorithm">Algorithms</a>. + <a href="http://en.wikipedia.org/wiki/Standard_Template_Library" target="_top">STL</a> + containers extend themselves in place though member functions such as <a class="link" href="algorithm/transformation/functions/push_back.html" title="push_back"><code class="computeroutput"><span class="identifier">push_back</span></code></a> and <a class="link" href="algorithm/transformation/functions/insert.html" title="insert"><code class="computeroutput"><span class="identifier">insert</span></code></a>. <a href="http://www.boost.org/libs/mpl/index.html" target="_top">MPL</a> + sequences, on the other hand, are extended through "intrinsic" functions + that actually return whole sequences. <a href="http://www.boost.org/libs/mpl/index.html" target="_top">MPL</a> + is purely functional and can not have side effects. For example, <a href="http://www.boost.org/libs/mpl/index.html" target="_top">MPL</a>'s + <code class="computeroutput"><span class="identifier">push_back</span></code> does not actually + mutate an <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">vector</span></code>. It can't do that. Instead, it returns + an extended <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">vector</span></code>. + </p> +<p> + Like <a href="http://www.boost.org/libs/mpl/index.html" target="_top">MPL</a>, Fusion + too is purely functional and can not have side effects. With runtime efficiency + in mind, Fusion sequences are extended through generic functions that return + <a class="link" href="view.html" title="View">Views</a>. <a class="link" href="view.html" title="View">Views</a> + are sequences that do not actually contain data, but instead impart an alternative + presentation over the data from one or more underlying sequences. <a class="link" href="view.html" title="View">Views</a> + are proxies. They provide an efficient yet purely functional way to work on + potentially expensive sequence operations. For example, given a <a class="link" href="container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a>, Fusion's <a class="link" href="algorithm/transformation/functions/push_back.html" title="push_back"><code class="computeroutput"><span class="identifier">push_back</span></code></a> returns a <a class="link" href="view/joint_view.html" title="joint_view"><code class="computeroutput"><span class="identifier">joint_view</span></code></a>, instead of an actual extended + <a class="link" href="container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a>. + A <a class="link" href="view/joint_view.html" title="joint_view"><code class="computeroutput"><span class="identifier">joint_view</span></code></a> + holds a reference to the original sequence plus the appended data --making + it very cheap to pass around. + </p> +<h4> +<a name="fusion.notes.h4"></a> + <span><a name="fusion.notes.element_conversion"></a></span><a class="link" href="notes.html#fusion.notes.element_conversion">Element + Conversion</a> + </h4> +<p> + Functions that take in elemental values to form sequences (e.g. <a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a>) convert their arguments + to something suitable to be stored as a sequence element. In general, the element + types are stored as plain values. Example: + </p> +<pre class="programlisting"><a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a><span class="special">(</span><span class="number">1</span><span class="special">,</span> <span class="char">'x'</span><span class="special">)</span> +</pre> +<p> + returns a <a class="link" href="container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a><code class="computeroutput"><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> + <span class="keyword">char</span><span class="special">></span></code>. + </p> +<p> + There are a few exceptions, however. + </p> +<p> + <span class="bold"><strong>Arrays:</strong></span> + </p> +<p> + Array arguments are deduced to reference to const types. For example <sup>[<a name="fusion.notes.f0" href="#ftn.fusion.notes.f0" class="footnote">13</a>]</sup>: + </p> +<pre class="programlisting"><a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a><span class="special">(</span><span class="string">"Donald"</span><span class="special">,</span> <span class="string">"Daisy"</span><span class="special">)</span> +</pre> +<p> + creates a <a class="link" href="container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a> + of type + </p> +<pre class="programlisting"><a class="link" href="container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a><span class="special"><</span><span class="keyword">const</span> <span class="keyword">char</span> <span class="special">(&)[</span><span class="number">7</span><span class="special">],</span> <span class="keyword">const</span> <span class="keyword">char</span> <span class="special">(&)[</span><span class="number">6</span><span class="special">]></span> +</pre> +<p> + <span class="bold"><strong>Function pointers:</strong></span> + </p> +<p> + Function pointers are deduced to the plain non-reference type (i.e. to plain + function pointer). Example: + </p> +<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">f</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span><span class="special">);</span> + <span class="special">...</span> +<a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a><span class="special">(&</span><span class="identifier">f</span><span class="special">);</span> +</pre> +<p> + creates a <a class="link" href="container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a> + of type + </p> +<pre class="programlisting"><a class="link" href="container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a><span class="special"><</span><span class="keyword">void</span> <span class="special">(*)(</span><span class="keyword">int</span><span class="special">)></span> +</pre> +<h4> +<a name="fusion.notes.h5"></a> + <span><a name="fusion.notes.boost__ref"></a></span><a class="link" href="notes.html#fusion.notes.boost__ref">boost::ref</a> + </h4> +<p> + Fusion's generation functions (e.g. <a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a>) by default stores the element + types as plain non-reference types. Example: + </p> +<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">foo</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">A</span><span class="special">&</span> <span class="identifier">a</span><span class="special">,</span> <span class="identifier">B</span><span class="special">&</span> <span class="identifier">b</span><span class="special">)</span> <span class="special">{</span> + <span class="special">...</span> + <a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a><span class="special">(</span><span class="identifier">a</span><span class="special">,</span> <span class="identifier">b</span><span class="special">)</span> +</pre> +<p> + creates a <a class="link" href="container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a> + of type + </p> +<pre class="programlisting"><a class="link" href="container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a><span class="special"><</span><span class="identifier">A</span><span class="special">,</span> <span class="identifier">B</span><span class="special">></span> +</pre> +<p> + Sometimes the plain non-reference type is not desired. You can use <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">ref</span></code> + and <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">cref</span></code> to store references or const references + (respectively) instead. The mechanism does not compromise const correctness + since a const object wrapped with ref results in a tuple element with const + reference type (see the fifth code line below). Examples: + </p> +<p> + For example: + </p> +<pre class="programlisting"><span class="identifier">A</span> <span class="identifier">a</span><span class="special">;</span> <span class="identifier">B</span> <span class="identifier">b</span><span class="special">;</span> <span class="keyword">const</span> <span class="identifier">A</span> <span class="identifier">ca</span> <span class="special">=</span> <span class="identifier">a</span><span class="special">;</span> +<a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a><span class="special">(</span><span class="identifier">cref</span><span class="special">(</span><span class="identifier">a</span><span class="special">),</span> <span class="identifier">b</span><span class="special">);</span> <span class="comment">// creates list<const A&, B></span> +<a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a><span class="special">(</span><span class="identifier">ref</span><span class="special">(</span><span class="identifier">a</span><span class="special">),</span> <span class="identifier">b</span><span class="special">);</span> <span class="comment">// creates list<A&, B></span> +<a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a><span class="special">(</span><span class="identifier">ref</span><span class="special">(</span><span class="identifier">a</span><span class="special">),</span> <span class="identifier">cref</span><span class="special">(</span><span class="identifier">b</span><span class="special">));</span> <span class="comment">// creates list<A&, const B&></span> +<a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a><span class="special">(</span><span class="identifier">cref</span><span class="special">(</span><span class="identifier">ca</span><span class="special">));</span> <span class="comment">// creates list<const A&></span> +<a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a><span class="special">(</span><span class="identifier">ref</span><span class="special">(</span><span class="identifier">ca</span><span class="special">));</span> <span class="comment">// creates list<const A&></span> +</pre> +<p> + See <a href="http://www.boost.org/doc/html/ref.html" target="_top">Boost.Ref</a> for + details. + </p> +<h4> +<a name="fusion.notes.h6"></a> + <span><a name="fusion.notes.adt_attribute_proxy"></a></span><a class="link" href="notes.html#fusion.notes.adt_attribute_proxy">adt_attribute_proxy</a> + </h4> +<p> + To adapt arbitrary data types that do not allow direct access to their members, + but allow indirect access via expressions (such as invocations of get- and + set-methods), fusion's <code class="literal">BOOST_FUSION_ADAPT_<span class="emphasis"><em>xxx</em></span>ADT<span class="emphasis"><em>xxx</em></span></code>-family + (e.g. <a class="link" href="adapted/adapt_adt.html" title="BOOST_FUSION_ADAPT_ADT"><code class="computeroutput"><span class="identifier">BOOST_FUSION_ADAPT_ADT</span></code></a>) + may be used. To bypass the restriction of not having actual lvalues that represent + the elements of the fusion sequence, but rather a sequence of paired expressions + that access the elements, the actual return type of fusion's intrinsic sequence + access functions (<a class="link" href="sequence/intrinsic/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a>, <a class="link" href="sequence/intrinsic/functions/at_c.html" title="at_c"><code class="computeroutput"><span class="identifier">at_c</span></code></a>, <a class="link" href="sequence/intrinsic/functions/at_key.html" title="at_key"><code class="computeroutput"><span class="identifier">at_key</span></code></a>, <a class="link" href="iterator/functions/deref.html" title="deref"><code class="computeroutput"><span class="identifier">deref</span></code></a>, and <a class="link" href="iterator/functions/deref_data.html" title="deref_data"><code class="computeroutput"><span class="identifier">deref_data</span></code></a>) is a proxy type, an instance + of <code class="computeroutput"><span class="identifier">adt_attribute_proxy</span></code>, that + encapsulates these expressions. + </p> +<p> + <code class="computeroutput"><span class="identifier">adt_attribute_proxy</span></code> is defined + in the namespace <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">fusion</span><span class="special">::</span><span class="identifier">extension</span></code> and has three template arguments: + </p> +<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">fusion</span> <span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">extension</span> +<span class="special">{</span> + <span class="keyword">template</span><span class="special"><</span> + <span class="keyword">typename</span> <span class="identifier">Type</span> + <span class="special">,</span> <span class="keyword">int</span> <span class="identifier">Index</span> + <span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">Const</span> + <span class="special">></span> + <span class="keyword">struct</span> <span class="identifier">adt_attribute_proxy</span><span class="special">;</span> +<span class="special">}}}</span> +</pre> +<p> + When adapting a class type, <code class="computeroutput"><span class="identifier">adt_attribute_proxy</span></code> + is specialized for every element of the adapted sequence, with <code class="computeroutput"><span class="identifier">Type</span></code> being the class type that is adapted, + <code class="computeroutput"><span class="identifier">Index</span></code> the 0-based indices of + the elements, and <code class="computeroutput"><span class="identifier">Const</span></code> both + <code class="computeroutput"><span class="keyword">true</span></code> and <code class="computeroutput"><span class="keyword">false</span></code>. + The return type of fusion's intrinsic sequence access functions for the <span class="emphasis"><em>N</em></span>th + element of an adapted class type <code class="computeroutput"><span class="identifier">type_name</span></code> + is <code class="literal">adt_attribute_proxy<type_name, <span class="emphasis"><em>N</em></span>, <span class="emphasis"><em>Const</em></span>></code>, + with <code class="literal"><span class="emphasis"><em>Const</em></span></code> being <code class="computeroutput"><span class="keyword">true</span></code> + for constant instances of <code class="computeroutput"><span class="identifier">type_name</span></code> + and <code class="computeroutput"><span class="keyword">false</span></code> for non-constant ones. + </p> +<div class="variablelist"> +<p class="title"><b>Notation</b></p> +<dl> +<dt><span class="term"><code class="computeroutput"><span class="identifier">type_name</span></code></span></dt> +<dd><p> + The type to be adapted, with M attributes + </p></dd> +<dt><span class="term"><code class="computeroutput"><span class="identifier">inst</span></code></span></dt> +<dd><p> + Object of type <code class="computeroutput"><span class="identifier">type_name</span></code> + </p></dd> +<dt><span class="term"><code class="computeroutput"><span class="identifier">const_inst</span></code></span></dt> +<dd><p> + Object of type <code class="computeroutput"><span class="identifier">type_name</span> <span class="keyword">const</span></code> + </p></dd> +<dt><span class="term"><code class="literal">(attribute_type<span class="emphasis"><em>N</em></span>, attribute_const_type<span class="emphasis"><em>N</em></span>, + get_expr<span class="emphasis"><em>N</em></span>, set_expr<span class="emphasis"><em>N</em></span>)</code></span></dt> +<dd><p> + Attribute descriptor of the <span class="emphasis"><em>N</em></span>th attribute of <code class="computeroutput"><span class="identifier">type_name</span></code> as passed to the adaption + macro, 0≤<span class="emphasis"><em>N</em></span><M + </p></dd> +<dt><span class="term"><code class="literal">proxy_type<span class="emphasis"><em>N</em></span></code></span></dt> +<dd><p> + <code class="literal">adt_attribute_proxy<type_name, <span class="emphasis"><em>N</em></span>, <code class="computeroutput"><span class="keyword">false</span></code>></code> with <span class="emphasis"><em>N</em></span> + being an integral constant, 0≤<span class="emphasis"><em>N</em></span><M + </p></dd> +<dt><span class="term"><code class="literal">const_proxy_type<span class="emphasis"><em>N</em></span></code></span></dt> +<dd><p> + <code class="literal">adt_attribute_proxy<type_name, <span class="emphasis"><em>N</em></span>, <code class="computeroutput"><span class="keyword">true</span></code>></code> with <span class="emphasis"><em>N</em></span> + being an integral constant, 0≤<span class="emphasis"><em>N</em></span><M + </p></dd> +<dt><span class="term"><code class="literal">proxy<span class="emphasis"><em>N</em></span></code></span></dt> +<dd><p> + Object of type <code class="literal">proxy_type<span class="emphasis"><em>N</em></span></code> + </p></dd> +<dt><span class="term"><code class="literal">const_proxy<span class="emphasis"><em>N</em></span></code></span></dt> +<dd><p> + Object of type <code class="literal">const_proxy_type<span class="emphasis"><em>N</em></span></code> + </p></dd> +</dl> +</div> +<p> + <span class="bold"><strong>Expression Semantics</strong></span> + </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="literal">proxy_type<span class="emphasis"><em>N</em></span>(inst)</code> + </p> + </td> +<td> + <p> + Creates an instance of <code class="literal">proxy_type<span class="emphasis"><em>N</em></span></code> + with underlying object <code class="computeroutput"><span class="identifier">inst</span></code> + </p> + </td> +</tr> +<tr> +<td> + <p> + <code class="literal">const_proxy_type<span class="emphasis"><em>N</em></span>(const_inst)</code> + </p> + </td> +<td> + <p> + Creates an instance of <code class="literal">const_proxy_type<span class="emphasis"><em>N</em></span></code> + with underlying object <code class="computeroutput"><span class="identifier">const_inst</span></code> + </p> + </td> +</tr> +<tr> +<td> + <p> + <code class="literal">proxy_type<span class="emphasis"><em>N</em></span>::type</code> + </p> + </td> +<td> + <p> + Another name for <code class="literal">attribute_type<span class="emphasis"><em>N</em></span></code> + </p> + </td> +</tr> +<tr> +<td> + <p> + <code class="literal">const_proxy_type<span class="emphasis"><em>N</em></span>::type</code> + </p> + </td> +<td> + <p> + Another name for <code class="literal">const_attribute_type<span class="emphasis"><em>N</em></span></code> + </p> + </td> +</tr> +<tr> +<td> + <p> + <code class="literal">proxy<span class="emphasis"><em>N</em></span>=t</code> + </p> + </td> +<td> + <p> + Invokes <code class="literal">set_expr<span class="emphasis"><em>N</em></span></code>, with + <code class="computeroutput"><span class="identifier">t</span></code> being an arbitrary + object. <code class="literal">set_expr<span class="emphasis"><em>N</em></span></code> may access + the variables named <code class="computeroutput"><span class="identifier">obj</span></code> + of type <code class="computeroutput"><span class="identifier">type_name</span><span class="special">&</span></code>, which represent the corresponding + instance of <code class="computeroutput"><span class="identifier">type_name</span></code>, + and <code class="computeroutput"><span class="identifier">val</span></code> of an arbitrary + const-qualified reference template type parameter <code class="computeroutput"><span class="identifier">Val</span></code>, + which represents <code class="computeroutput"><span class="identifier">t</span></code>. + </p> + </td> +</tr> +<tr> +<td> + <p> + <code class="literal">proxy<span class="emphasis"><em>N</em></span>.get()</code> + </p> + </td> +<td> + <p> + Invokes <code class="literal">get_expr<span class="emphasis"><em>N</em></span></code> and forwards + its return value. <code class="literal">get_expr<span class="emphasis"><em>N</em></span></code> + may access the variable named <code class="computeroutput"><span class="identifier">obj</span></code> + of type <code class="computeroutput"><span class="identifier">type_name</span><span class="special">&</span></code> which represents the underlying + instance of <code class="computeroutput"><span class="identifier">type_name</span></code>. + <code class="literal">attribute_type<span class="emphasis"><em>N</em></span></code> may specify + the type that <code class="literal">get_expr<span class="emphasis"><em>N</em></span></code> denotes + to. + </p> + </td> +</tr> +<tr> +<td> + <p> + <code class="literal">const_proxy<span class="emphasis"><em>N</em></span>.get()</code> + </p> + </td> +<td> + <p> + Invokes <code class="literal">get_expr<span class="emphasis"><em>N</em></span></code> and forwards + its return value. <code class="literal">get_expr<span class="emphasis"><em>N</em></span></code> + may access the variable named <code class="computeroutput"><span class="identifier">obj</span></code> + of type <code class="computeroutput"><span class="identifier">type_name</span> <span class="keyword">const</span><span class="special">&</span></code> + which represents the underlying instance of <code class="computeroutput"><span class="identifier">type_name</span></code>. + <code class="literal">attribute_const_type<span class="emphasis"><em>N</em></span></code> may + specify the type that <code class="literal">get_expr<span class="emphasis"><em>N</em></span></code> + denotes to. + </p> + </td> +</tr> +</tbody> +</table></div> +<p> + Additionally, <code class="literal">proxy_type<span class="emphasis"><em>N</em></span></code> and <code class="literal">const_proxy_type<span class="emphasis"><em>N</em></span></code> + are copy constructible, copy assignable and implicitly convertible to <code class="literal">proxy_type<span class="emphasis"><em>N</em></span>::type</code> + or <code class="literal">const_proxy_type<span class="emphasis"><em>N</em></span>::type</code>. + </p> +<div class="tip"><table border="0" summary="Tip"> +<tr> +<td rowspan="2" align="center" valign="top" width="25"><img alt="[Tip]" src="../../../../../doc/src/images/tip.png"></td> +<th align="left">Tip</th> +</tr> +<tr><td align="left" valign="top"><p> + To avoid the pitfalls of the proxy type, an arbitrary class type may also + be adapted directly using fusion's <a class="link" href="extension.html" title="Extension">intrinsic + extension mechanism</a>. + </p></td></tr> +</table></div> +<div class="footnotes"> +<br><hr width="100" align="left"> +<div class="footnote"><p><sup>[<a id="ftn.fusion.notes.f0" href="#fusion.notes.f0" class="para">13</a>] </sup> + Note that the type of a string literal is an array of const characters, not + <code class="computeroutput"><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span></code>. To get <a class="link" href="container/generation/functions/make_list.html" title="make_list"><code class="computeroutput"><span class="identifier">make_list</span></code></a> to create a <a class="link" href="container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a> with an element of a non-const + array type one must use the <code class="computeroutput"><span class="identifier">ref</span></code> + wrapper (see <a class="link" href="notes.html#fusion.notes.boost__ref"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">ref</span></code></a>). + </p></div> +</div> +</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 © 2001-2006, 2011 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="functional/generation/metafunctions/mk_unfused.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="change_log.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +</body> +</html> |