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| 26 | <div class="titlepage"><div> |
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| 27 | <div><h2 class="title"> |
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| 28 | <a name="lambda"></a>Chapter 6. Boost.Lambda</h2></div> |
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| 29 | <div><div class="author"> |
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| 30 | <h3 class="author"> |
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| 31 | <span class="firstname">Jaakko</span> <span class="surname">Järvi</span> |
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| 32 | </h3> |
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| 33 | <code class="email"><<a href="mailto:jarvi%20at%20cs%20tamu%20edu">jarvi at cs tamu edu</a>></code> |
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| 34 | </div></div> |
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| 35 | <div><p class="copyright">Copyright © 1999-2004 Jaakko Järvi, Gary Powell</p></div> |
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| 36 | <div><div class="legalnotice"> |
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| 37 | <a name="id2706954"></a><p>Use, modification and distribution is subject to the Boost |
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| 38 | Software License, Version 1.0. (See accompanying file |
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| 39 | <code class="filename">LICENSE_1_0.txt</code> 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> |
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| 40 | </div></div> |
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| 41 | </div></div> |
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| 42 | <div class="toc"> |
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| 43 | <p><b>Table of Contents</b></p> |
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| 44 | <dl> |
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| 45 | <dt><span class="section"><a href="lambda.html#introduction">In a nutshell</a></span></dt> |
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| 46 | <dt><span class="section"><a href="lambda/getting_started.html">Getting Started</a></span></dt> |
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| 47 | <dd><dl> |
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| 48 | <dt><span class="section"><a href="lambda/getting_started.html#id2707059">Installing the library</a></span></dt> |
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| 49 | <dt><span class="section"><a href="lambda/getting_started.html#id2707319">Conventions used in this document</a></span></dt> |
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| 50 | </dl></dd> |
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| 51 | <dt><span class="section"><a href="lambda/s03.html">Introduction</a></span></dt> |
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| 52 | <dd><dl> |
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| 53 | <dt><span class="section"><a href="lambda/s03.html#id2707350">Motivation</a></span></dt> |
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| 54 | <dt><span class="section"><a href="lambda/s03.html#id2707599">Introduction to lambda expressions</a></span></dt> |
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| 55 | </dl></dd> |
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| 56 | <dt><span class="section"><a href="lambda/using_library.html">Using the library</a></span></dt> |
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| 57 | <dd><dl> |
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| 58 | <dt><span class="section"><a href="lambda/using_library.html#lambda.introductory_examples">Introductory Examples</a></span></dt> |
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| 59 | <dt><span class="section"><a href="lambda/using_library.html#lambda.parameter_and_return_types">Parameter and return types of lambda functors</a></span></dt> |
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| 60 | <dt><span class="section"><a href="lambda/using_library.html#lambda.actual_arguments_to_lambda_functors">About actual arguments to lambda functors</a></span></dt> |
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| 61 | <dt><span class="section"><a href="lambda/using_library.html#lambda.storing_bound_arguments">Storing bound arguments in lambda functions</a></span></dt> |
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| 62 | </dl></dd> |
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| 63 | <dt><span class="section"><a href="lambda/le_in_details.html">Lambda expressions in details</a></span></dt> |
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| 64 | <dd><dl> |
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| 65 | <dt><span class="section"><a href="lambda/le_in_details.html#lambda.placeholders">Placeholders</a></span></dt> |
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| 66 | <dt><span class="section"><a href="lambda/le_in_details.html#lambda.operator_expressions">Operator expressions</a></span></dt> |
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| 67 | <dt><span class="section"><a href="lambda/le_in_details.html#lambda.bind_expressions">Bind expressions</a></span></dt> |
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| 68 | <dt><span class="section"><a href="lambda/le_in_details.html#lambda.overriding_deduced_return_type">Overriding the deduced return type</a></span></dt> |
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| 69 | <dt><span class="section"><a href="lambda/le_in_details.html#lambda.delaying_constants_and_variables">Delaying constants and variables</a></span></dt> |
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| 70 | <dt><span class="section"><a href="lambda/le_in_details.html#lambda.lambda_expressions_for_control_structures">Lambda expressions for control structures</a></span></dt> |
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| 71 | <dt><span class="section"><a href="lambda/le_in_details.html#lambda.exceptions">Exceptions</a></span></dt> |
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| 72 | <dt><span class="section"><a href="lambda/le_in_details.html#lambda.construction_and_destruction">Construction and destruction</a></span></dt> |
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| 73 | <dt><span class="section"><a href="lambda/le_in_details.html#id2711160">Special lambda expressions</a></span></dt> |
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| 74 | <dt><span class="section"><a href="lambda/le_in_details.html#id2711604">Casts, sizeof and typeid</a></span></dt> |
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| 75 | <dt><span class="section"><a href="lambda/le_in_details.html#lambda.nested_stl_algorithms">Nesting STL algorithm invocations</a></span></dt> |
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| 76 | </dl></dd> |
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| 77 | <dt><span class="section"><a href="lambda/extending.html">Extending return type deduction system</a></span></dt> |
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| 78 | <dt><span class="section"><a href="lambda/s07.html">Practical considerations</a></span></dt> |
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| 79 | <dd><dl> |
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| 80 | <dt><span class="section"><a href="lambda/s07.html#id2712759">Performance</a></span></dt> |
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| 81 | <dt><span class="section"><a href="lambda/s07.html#id2713087">About compiling</a></span></dt> |
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| 82 | <dt><span class="section"><a href="lambda/s07.html#id2713129">Portability</a></span></dt> |
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| 83 | </dl></dd> |
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| 84 | <dt><span class="section"><a href="lambda/s08.html">Relation to other Boost libraries</a></span></dt> |
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| 85 | <dd><dl> |
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| 86 | <dt><span class="section"><a href="lambda/s08.html#id2713388">Boost Function</a></span></dt> |
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| 87 | <dt><span class="section"><a href="lambda/s08.html#id2713474">Boost Bind</a></span></dt> |
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| 88 | </dl></dd> |
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| 89 | <dt><span class="section"><a href="lambda/s09.html">Contributors</a></span></dt> |
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| 90 | <dt><span class="appendix"><a href="apa.html">A. Rationale for some of the design decisions</a></span></dt> |
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| 91 | <dd><dl><dt><span class="section"><a href="apa.html#lambda.why_weak_arity"> |
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| 92 | Lambda functor arity |
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| 93 | </a></span></dt></dl></dd> |
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| 94 | <dt><span class="bibliography"><a href="lambda.html#id2713747">Bibliography</a></span></dt> |
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| 95 | </dl> |
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| 96 | </div> |
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| 97 | <div class="section" lang="en"> |
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| 98 | <div class="titlepage"><div><div><h3 class="title"> |
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| 99 | <a name="introduction"></a>In a nutshell</h3></div></div></div> |
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| 100 | <p> |
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| 101 | |
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| 102 | The Boost Lambda Library (BLL in the sequel) is a C++ template |
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| 103 | library, which implements form of <span class="emphasis"><em>lambda abstractions</em></span> for C++. |
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| 104 | The term originates from functional programming and lambda calculus, where a lambda abstraction defines an unnamed function. |
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| 105 | The primary motivation for the BLL is to provide flexible and |
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| 106 | convenient means to define unnamed function objects for STL algorithms. |
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| 107 | In explaining what the library is about, a line of code says more than a thousand words; the |
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| 108 | following line outputs the elements of some STL container |
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| 109 | <code class="literal">a</code> separated by spaces: |
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| 110 | |
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| 111 | </p> |
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| 112 | <pre class="programlisting">for_each(a.begin(), a.end(), std::cout << _1 << ' ');</pre> |
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| 113 | <p> |
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| 114 | |
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| 115 | The expression <code class="literal">std::cout << _1 << ' '</code> defines a unary function object. |
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| 116 | The variable <code class="literal">_1</code> is the parameter of this function, a <span class="emphasis"><em>placeholder</em></span> for the actual argument. |
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| 117 | Within each iteration of <code class="literal">for_each</code>, the function is |
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| 118 | called with an element of <code class="literal">a</code> as the actual argument. |
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| 119 | This actual argument is substituted for the placeholder, and the “<span class="quote">body</span>” of the function is evaluated. |
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| 120 | </p> |
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| 121 | <p>The essence of BLL is letting you define small unnamed function objects, such as the one above, directly on the call site of an STL algorithm. |
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| 122 | </p> |
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| 123 | </div> |
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| 124 | <div class="bibliography"> |
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| 125 | <div class="titlepage"><div><div><h2 class="title"> |
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| 126 | <a name="id2713747"></a>Bibliography</h2></div></div></div> |
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| 127 | <div class="biblioentry"> |
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| 128 | <a name="cit:stepanov:94"></a><p>[<span class="abbrev">STL94</span>] <span class="authorgroup"><span class="firstname">A. A.</span> <span class="surname">Stepanov</span> and <span class="firstname">M.</span> <span class="surname">Lee</span>. </span><span class="title"><i>The Standard Template Library</i>. </span><span class="orgname">Hewlett-Packard Laboratories. </span><span class="pubdate">1994. </span><span class="bibliomisc"><a href="http://www.hpl.hp.com/techreports" target="_top">www.hpl.hp.com/techreports</a>. </span></p> |
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| 129 | </div> |
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| 130 | <div class="biblioentry"> |
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| 131 | <a name="cit:sgi:02"></a><p>[<span class="abbrev">SGI02</span>] <span class="title"><i>The SGI Standard Template Library</i>. </span><span class="pubdate">2002. </span><span class="bibliomisc"><a href="http://www.sgi.com/tech/stl/" target="_top">www.sgi.com/tech/stl/</a>. </span></p> |
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| 132 | </div> |
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| 133 | <div class="biblioentry"> |
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| 134 | <a name="cit:c++:98"></a><p>[<span class="abbrev">C++98</span>] <span class="title"><i>International Standard, Programming Languages – C++</i>. </span><span class="subtitle">ISO/IEC:14882. </span><span class="pubdate">1998. </span></p> |
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| 135 | </div> |
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| 136 | <div class="biblioentry"> |
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| 137 | <a name="cit:jarvi:99"></a><p>[<span class="abbrev">Jär99</span>] <span class="articleinfo"><span class="author"><span class="firstname">Jaakko</span> <span class="surname">Järvi</span>. </span><span class="title"><i>C++ Function Object Binders Made Easy</i>. </span>. </span><span class="title"><i>Lecture Notes in Computer Science</i>. </span><span class="volumenum">1977. </span><span class="publishername">Springer. </span><span class="pubdate">2000. </span></p> |
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| 138 | </div> |
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| 139 | <div class="biblioentry"> |
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| 140 | <a name="cit:jarvi:00"></a><p>[<span class="abbrev">Jär00</span>] <span class="author"><span class="firstname">Jaakko</span> <span class="surname">Järvi</span>. </span><span class="author"><span class="firstname">Gary</span> <span class="surname">Powell</span>. </span><span class="title"><i>The Lambda Library : Lambda Abstraction in C++</i>. </span><span class="orgname">Turku Centre for Computer Science. </span><span class="bibliomisc">Technical Report . </span><span class="issuenum">378. </span><span class="pubdate">2000. </span><span class="bibliomisc"><a href="http://www.tucs.fi/Publications/techreports/TR378.php" target="_top">www.tucs.fi/publications</a>. </span></p> |
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| 141 | </div> |
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| 142 | <div class="biblioentry"> |
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| 143 | <a name="cit:jarvi:01"></a><p>[<span class="abbrev">Jär01</span>] <span class="author"><span class="firstname">Jaakko</span> <span class="surname">Järvi</span>. </span><span class="author"><span class="firstname">Gary</span> <span class="surname">Powell</span>. </span><span class="title"><i>The Lambda Library : Lambda Abstraction in C++</i>. </span><span class="confgroup"><span class="conftitle">Second Workshop on C++ Template Programming. </span><span class="address">Tampa Bay, OOPSLA'01. </span>. </span><span class="pubdate">2001. </span><span class="bibliomisc"><a href="http://www.oonumerics.org/tmpw01/" target="_top">www.oonumerics.org/tmpw01/</a>. </span></p> |
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| 144 | </div> |
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| 145 | <div class="biblioentry"> |
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| 146 | <a name="cit:jarvi:03"></a><p>[<span class="abbrev">Jär03</span>] <span class="articleinfo"><span class="author"><span class="firstname">Jaakko</span> <span class="surname">Järvi</span>. </span><span class="author"><span class="firstname">Gary</span> <span class="surname">Powell</span>. </span><span class="author"><span class="firstname">Andrew</span> <span class="surname">Lumsdaine</span>. </span><span class="title"><i>The Lambda Library : unnamed functions in C++</i>. </span>. </span><span class="title"><i>Software - Practice and Expreience</i>. </span><span class="volumenum">33:259-291. </span><span class="pubdate">2003. </span></p> |
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| 147 | </div> |
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| 148 | <div class="biblioentry"> |
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| 149 | <a name="cit:boost::tuple"></a><p>[<span class="abbrev">tuple</span>] <span class="title"><i>The Boost Tuple Library</i>. </span><span class="bibliomisc"><a href="http://www.boost.org/libs/tuple/doc/tuple_users_guide.html" target="_top">www.boost.org/libs/tuple/doc/tuple_users_guide.html</a>. </span><span class="pubdate">2002. </span></p> |
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| 150 | </div> |
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| 151 | <div class="biblioentry"> |
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| 152 | <a name="cit:boost::type_traits"></a><p>[<span class="abbrev">type_traits</span>] <span class="title"><i>The Boost type_traits</i>. </span><span class="bibliomisc"><a href="http://www.boost.org/libs/type_traits/index.htm" target="_top">www.boost.org/libs/type_traits/</a>. </span><span class="pubdate">2002. </span></p> |
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| 153 | </div> |
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| 154 | <div class="biblioentry"> |
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| 155 | <a name="cit:boost::ref"></a><p>[<span class="abbrev">ref</span>] <span class="title"><i>Boost ref</i>. </span><span class="bibliomisc"><a href="http://www.boost.org/libs/bind/ref.html" target="_top">www.boost.org/libs/bind/ref.html</a>. </span><span class="pubdate">2002. </span></p> |
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| 156 | </div> |
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| 157 | <div class="biblioentry"> |
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| 158 | <a name="cit:boost::bind"></a><p>[<span class="abbrev">bind</span>] <span class="title"><i>Boost Bind Library</i>. </span><span class="bibliomisc"><a href="http://www.boost.org/libs/bind/bind.html" target="_top">www.boost.org/libs/bind/bind.html</a>. </span><span class="pubdate">2002. </span></p> |
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| 159 | </div> |
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| 160 | <div class="biblioentry"> |
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| 161 | <a name="cit:boost::function"></a><p>[<span class="abbrev">function</span>] <span class="title"><i>Boost Function Library</i>. </span><span class="bibliomisc"><a href="http://www.boost.org/libs/function/" target="_top">www.boost.org/libs/function/</a>. </span><span class="pubdate">2002. </span></p> |
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| 162 | </div> |
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| 163 | <div class="biblioentry"> |
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| 164 | <a name="cit:fc++"></a><p>[<span class="abbrev">fc++</span>] <span class="title"><i>The FC++ library: Functional Programming in C++</i>. </span><span class="author"><span class="firstname">Yannis</span> <span class="surname">Smaragdakis</span>. </span><span class="author"><span class="firstname">Brian</span> <span class="surname">McNamara</span>. </span><span class="bibliomisc"><a href="http://www.cc.gatech.edu/~yannis/fc++/" target="_top">www.cc.gatech.edu/~yannis/fc++/</a>. </span><span class="pubdate">2002. </span></p> |
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| 165 | </div> |
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| 166 | </div> |
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| 167 | </div> |
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| 168 | <table width="100%"><tr> |
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| 169 | <td align="left"><small><p>Last revised: November 28, 2004 at 03:29:16 GMT</p></small></td> |
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| 170 | <td align="right"><small></small></td> |
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| 171 | </tr></table> |
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| 172 | <hr> |
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