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add nested typedefs

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[SVN r23644]
This commit is contained in:
Dave Abrahams
2004-07-16 19:58:03 +00:00
parent 2241bb1ae3
commit 700db48ac7
12 changed files with 537 additions and 474 deletions
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5
doc/facade-and-adaptor.html
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@ -614,7 +614,7 @@ template <
, class Difference = ptrdiff_t
>
class iterator_facade {
public:
public:
typedef remove_const<Value>::type value_type;
typedef Reference reference;
typedef Value* pointer;
@ -631,6 +631,8 @@ public:
Derived& operator+=(difference_type n);
Derived& operator-=(difference_type n);
Derived operator-(difference_type n) const;
protected:
typedef iterator_facade iterator_facade_;
};
// Comparison operators
@ -1202,6 +1204,7 @@ class iterator_adaptor
explicit iterator_adaptor(Base iter);
Base const& base() const;
protected:
typedef iterator_adaptor iterator_adaptor_;
Base const& base_reference() const;
Base& base_reference();
private: // Core iterator interface for iterator_facade.

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38
doc/iterator_adaptor.html
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@ -3,7 +3,7 @@
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="generator" content="Docutils 0.3.1: http://docutils.sourceforge.net/" />
<meta name="generator" content="Docutils 0.3.4: http://docutils.sourceforge.net/" />
<title>Iterator Adaptor</title>
<meta name="author" content="David Abrahams, Jeremy Siek, Thomas Witt" />
<meta name="organization" content="Boost Consulting, Indiana University Open Systems Lab, University of Hanover Institute for Transport Railway Operation and Construction" />
@ -12,7 +12,6 @@
<link rel="stylesheet" href="default.css" type="text/css" />
</head>
<body>
<div class="document" id="iterator-adaptor">
<h1 class="title">Iterator Adaptor</h1>
<table class="docinfo" frame="void" rules="none">
<col class="docinfo-name" />
@ -32,6 +31,7 @@ Railway Operation and Construction</a></td></tr>
<td>Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003. All rights reserved</td></tr>
</tbody>
</table>
<div class="document" id="iterator-adaptor">
<table class="field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
@ -55,7 +55,7 @@ depends on the operations supported by the <tt class="literal"><span class="pre"
core interface functions of <tt class="literal"><span class="pre">iterator_facade</span></tt> are redefined in the
<tt class="literal"><span class="pre">Derived</span></tt> class.</p>
<div class="contents topic" id="table-of-contents">
<p class="topic-title"><a name="table-of-contents">Table of Contents</a></p>
<p class="topic-title first"><a name="table-of-contents">Table of Contents</a></p>
<ul class="simple">
<li><a class="reference" href="#overview" id="id6" name="id6">Overview</a></li>
<li><a class="reference" href="#reference" id="id7" name="id7">Reference</a><ul>
@ -135,6 +135,7 @@ class iterator_adaptor
explicit iterator_adaptor(Base iter);
Base const&amp; base() const;
protected:
typedef iterator_adaptor iterator_adaptor_;
Base const&amp; base_reference() const;
Base&amp; base_reference();
private: // Core iterator interface for iterator_facade.
@ -339,7 +340,7 @@ template we developed in the <a class="reference" href="iterator_facade.html#tut
read that material, you should go back now and check it out because
we're going to pick up right where it left off.</p>
<div class="sidebar">
<p class="sidebar-title"><tt class="literal"><span class="pre">node_base*</span></tt> really <em>is</em> an iterator</p>
<p class="sidebar-title first"><tt class="literal"><span class="pre">node_base*</span></tt> really <em>is</em> an iterator</p>
<p>It's not really a very interesting iterator, since <tt class="literal"><span class="pre">node_base</span></tt>
is an abstract class: a pointer to a <tt class="literal"><span class="pre">node_base</span></tt> just points
at some base subobject of an instance of some other class, and
@ -349,7 +350,7 @@ position is to compare another <tt class="literal"><span class="pre">node_base*<
words, the original iterator traverses a one-element array.</p>
</div>
<p>You probably didn't think of it this way, but the <tt class="literal"><span class="pre">node_base*</span></tt>
object which underlies <tt class="literal"><span class="pre">node_iterator</span></tt> is itself an iterator,
object that underlies <tt class="literal"><span class="pre">node_iterator</span></tt> is itself an iterator,
just like all other pointers. If we examine that pointer closely
from an iterator perspective, we can see that it has much in common
with the <tt class="literal"><span class="pre">node_iterator</span></tt> we're building. First, they share most
@ -358,9 +359,10 @@ of the same associated types (<tt class="literal"><span class="pre">value_type</
core functionality is the same: <tt class="literal"><span class="pre">operator*</span></tt> and <tt class="literal"><span class="pre">operator==</span></tt> on
the <tt class="literal"><span class="pre">node_iterator</span></tt> return the result of invoking the same
operations on the underlying pointer, via the <tt class="literal"><span class="pre">node_iterator</span></tt>'s
<a class="reference" href="iterator_facade.html#implementing-the-core-operations"><tt class="literal"><span class="pre">dereference</span></tt> and <tt class="literal"><span class="pre">equal</span></tt> member functions</a>). However, the <tt class="literal"><span class="pre">operator++</span></tt> for
<tt class="literal"><span class="pre">node_iterator</span></tt> behaves differently than for <tt class="literal"><span class="pre">node_base*</span></tt>
since it follows the <tt class="literal"><span class="pre">m_next</span></tt> pointer.</p>
<a class="reference" href="iterator_facade.html#implementing-the-core-operations"><tt class="literal"><span class="pre">dereference</span></tt> and <tt class="literal"><span class="pre">equal</span></tt> member functions</a>). The only real behavioral difference
between <tt class="literal"><span class="pre">node_base*</span></tt> and <tt class="literal"><span class="pre">node_iterator</span></tt> can be observed when
they are incremented: <tt class="literal"><span class="pre">node_iterator</span></tt> follows the
<tt class="literal"><span class="pre">m_next</span></tt> pointer, while <tt class="literal"><span class="pre">node_base*</span></tt> just applies an address offset.</p>
<p>It turns out that the pattern of building an iterator on another
iterator-like type (the <tt class="literal"><span class="pre">Base</span></tt> <a class="footnote-reference" href="#base" id="id3" name="id3"><sup>1</sup></a> type) while modifying
just a few aspects of the underlying type's behavior is an
@ -384,16 +386,12 @@ class node_iter
private:
struct enabler {}; // a private type avoids misuse
typedef boost::iterator_adaptor&lt;
node_iter&lt;Value&gt;, Value*, boost::use_default, boost::forward_traversal_tag
&gt; super_t;
public:
node_iter()
: super_t(0) {}
: node_iter::iterator_adaptor_(0) {}
explicit node_iter(Value* p)
: super_t(p) {}
: node_iter::iterator_adaptor_(p) {}
template &lt;class OtherValue&gt;
node_iter(
@ -403,14 +401,20 @@ class node_iter
, enabler
&gt;::type = enabler()
)
: super_t(other.base()) {}
: node_iter::iterator_adaptor_(other.base()) {}
private:
friend class boost::iterator_core_access;
void increment() { this-&gt;base_reference() = this-&gt;base()-&gt;next(); }
};
</pre>
<p>You can see an example program which exercises this version of the
<p>Note the use of <tt class="literal"><span class="pre">node_iter::iterator_adaptor_</span></tt> here: because
<tt class="literal"><span class="pre">iterator_adaptor</span></tt> defines a nested <tt class="literal"><span class="pre">iterator_adaptor_</span></tt> type
that refers to itself, that gives us a convenient way to refer to
the complicated base class type of <tt class="literal"><span class="pre">node_iter&lt;Value&gt;</span></tt>. [Note:
this technique is known not to work with Borland C++ 5.6.4 and
Metrowerks CodeWarrior versions prior to 9.0]</p>
<p>You can see an example program that exercises this version of the
node iterators <a class="reference" href="../example/node_iterator3.cpp">here</a>.</p>
<p>In the case of <tt class="literal"><span class="pre">node_iter</span></tt>, it's not very compelling to pass
<tt class="literal"><span class="pre">boost::use_default</span></tt> as <tt class="literal"><span class="pre">iterator_adaptor</span></tt>'s <tt class="literal"><span class="pre">Value</span></tt>
@ -423,7 +427,7 @@ iterator type argument and reverses its direction of traversal,
since the original iterator and the reversed one have all the same
associated types, <tt class="literal"><span class="pre">iterator_adaptor</span></tt>'s delegation of default
types to its <tt class="literal"><span class="pre">Base</span></tt> saves the implementor of
<tt class="literal"><span class="pre">boost::reverse_iterator</span></tt> from writing</p>
<tt class="literal"><span class="pre">boost::reverse_iterator</span></tt> from writing:</p>
<pre class="literal-block">
std::iterator_traits&lt;Iterator&gt;::<em>some-associated-type</em>
</pre>

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1
doc/iterator_adaptor_ref.rst
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@ -23,6 +23,7 @@
explicit iterator_adaptor(Base iter);
Base const& base() const;
protected:
typedef iterator_adaptor iterator_adaptor\_;
Base const& base_reference() const;
Base& base_reference();
private: // Core iterator interface for iterator_facade.

30
doc/iterator_adaptor_tutorial.rst
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@ -21,7 +21,7 @@ we're going to pick up right where it left off.
words, the original iterator traverses a one-element array.
You probably didn't think of it this way, but the ``node_base*``
object which underlies ``node_iterator`` is itself an iterator,
object that underlies ``node_iterator`` is itself an iterator,
just like all other pointers. If we examine that pointer closely
from an iterator perspective, we can see that it has much in common
with the ``node_iterator`` we're building. First, they share most
@ -30,9 +30,10 @@ of the same associated types (``value_type``, ``reference``,
core functionality is the same: ``operator*`` and ``operator==`` on
the ``node_iterator`` return the result of invoking the same
operations on the underlying pointer, via the ``node_iterator``\ 's
|dereference_and_equal|_). However, the ``operator++`` for
``node_iterator`` behaves differently than for ``node_base*``
since it follows the ``m_next`` pointer.
|dereference_and_equal|_). The only real behavioral difference
between ``node_base*`` and ``node_iterator`` can be observed when
they are incremented: ``node_iterator`` follows the
``m_next`` pointer, while ``node_base*`` just applies an address offset.
.. |dereference_and_equal| replace:: ``dereference`` and ``equal`` member functions
.. _dereference_and_equal: iterator_facade.html#implementing-the-core-operations
@ -60,16 +61,12 @@ behaviors other than ``increment``. The implementation of
private:
struct enabler {}; // a private type avoids misuse
typedef boost::iterator_adaptor<
node_iter<Value>, Value*, boost::use_default, boost::forward_traversal_tag
> super_t;
public:
node_iter()
: super_t(0) {}
: node_iter::iterator_adaptor_(0) {}
explicit node_iter(Value* p)
: super_t(p) {}
: node_iter::iterator_adaptor_(p) {}
template <class OtherValue>
node_iter(
@ -79,14 +76,21 @@ behaviors other than ``increment``. The implementation of
, enabler
>::type = enabler()
)
: super_t(other.base()) {}
: node_iter::iterator_adaptor_(other.base()) {}
private:
friend class boost::iterator_core_access;
void increment() { this->base_reference() = this->base()->next(); }
};
You can see an example program which exercises this version of the
Note the use of ``node_iter::iterator_adaptor_`` here: because
``iterator_adaptor`` defines a nested ``iterator_adaptor_`` type
that refers to itself, that gives us a convenient way to refer to
the complicated base class type of ``node_iter<Value>``. [Note:
this technique is known not to work with Borland C++ 5.6.4 and
Metrowerks CodeWarrior versions prior to 9.0]
You can see an example program that exercises this version of the
node iterators `here`__.
__ ../example/node_iterator3.cpp
@ -102,7 +106,7 @@ iterator type argument and reverses its direction of traversal,
since the original iterator and the reversed one have all the same
associated types, ``iterator_adaptor``\ 's delegation of default
types to its ``Base`` saves the implementor of
``boost::reverse_iterator`` from writing
``boost::reverse_iterator`` from writing:
.. parsed-literal::

21
doc/iterator_facade.html
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@ -3,7 +3,7 @@
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="generator" content="Docutils 0.3.1: http://docutils.sourceforge.net/" />
<meta name="generator" content="Docutils 0.3.4: http://docutils.sourceforge.net/" />
<title>Iterator Facade</title>
<meta name="author" content="David Abrahams, Jeremy Siek, Thomas Witt" />
<meta name="organization" content="Boost Consulting, Indiana University Open Systems Lab, University of Hanover Institute for Transport Railway Operation and Construction" />
@ -12,7 +12,6 @@
<link rel="stylesheet" href="default.css" type="text/css" />
</head>
<body>
<div class="document" id="iterator-facade">
<h1 class="title">Iterator Facade</h1>
<table class="docinfo" frame="void" rules="none">
<col class="docinfo-name" />
@ -32,6 +31,7 @@ Railway Operation and Construction</a></td></tr>
<td>Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003. All rights reserved</td></tr>
</tbody>
</table>
<div class="document" id="iterator-facade">
<table class="field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
@ -43,7 +43,7 @@ and associated types, to be supplied by a derived iterator class.</td>
</tbody>
</table>
<div class="contents topic" id="table-of-contents">
<p class="topic-title"><a name="table-of-contents">Table of Contents</a></p>
<p class="topic-title first"><a name="table-of-contents">Table of Contents</a></p>
<ul class="simple">
<li><a class="reference" href="#overview" id="id23" name="id23">Overview</a><ul>
<li><a class="reference" href="#usage" id="id24" name="id24">Usage</a></li>
@ -143,7 +143,7 @@ of the derived iterator type. These member functions are described
briefly below and in more detail in the iterator facade
requirements.</p>
<blockquote>
<table border class="table">
<table border="1" class="table">
<colgroup>
<col width="44%" />
<col width="56%" />
@ -261,7 +261,6 @@ are described in terms of a set of requirements, which must be
satisfied by the <tt class="literal"><span class="pre">iterator_facade</span></tt> implementation.</p>
<table class="citation" frame="void" id="cop95" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<col />
<tbody valign="top">
<tr><td class="label"><a name="cop95">[Cop95]</a></td><td><em>(<a class="fn-backref" href="#id1">1</a>, <a class="fn-backref" href="#id10">2</a>)</em> [Coplien, 1995] Coplien, J., Curiously Recurring Template
Patterns, C++ Report, February 1995, pp. 24-27.</td></tr>
@ -284,7 +283,7 @@ template &lt;
, class Difference = ptrdiff_t
&gt;
class iterator_facade {
public:
public:
typedef remove_const&lt;Value&gt;::type value_type;
typedef Reference reference;
typedef Value* pointer;
@ -301,6 +300,8 @@ public:
Derived&amp; operator+=(difference_type n);
Derived&amp; operator-=(difference_type n);
Derived operator-(difference_type n) const;
protected:
typedef iterator_facade iterator_facade_;
};
// Comparison operators
@ -444,8 +445,8 @@ object of a single pass iterator type interoperable with <tt class="literal"><sp
is a constant object of a random access traversal iterator type
interoperable with <tt class="literal"><span class="pre">X</span></tt>.</p>
<a class="target" id="core-operations" name="core-operations"></a><div class="topic">
<p class="topic-title"><tt class="literal"><span class="pre">iterator_facade</span></tt> Core Operations</p>
<table border class="table">
<p class="topic-title first"><tt class="literal"><span class="pre">iterator_facade</span></tt> Core Operations</p>
<table border="1" class="table">
<colgroup>
<col width="21%" />
<col width="23%" />
@ -1089,7 +1090,7 @@ iterator! For a working example of its use, see <a class="reference" href="../e
<div class="section" id="a-constant-node-iterator">
<h2><a class="toc-backref" href="#id42" name="a-constant-node-iterator">A constant <tt class="literal"><span class="pre">node_iterator</span></tt></a></h2>
<div class="sidebar">
<p class="sidebar-title">Constant and Mutable iterators</p>
<p class="sidebar-title first">Constant and Mutable iterators</p>
<p>The term <strong>mutable iterator</strong> means an iterator through which
the object it references (its &quot;referent&quot;) can be modified. A
<strong>constant iterator</strong> is one which doesn't allow modification of
@ -1139,7 +1140,7 @@ class const_node_iterator
};
</pre>
<div class="sidebar">
<p class="sidebar-title"><tt class="literal"><span class="pre">const</span></tt> and an iterator's <tt class="literal"><span class="pre">value_type</span></tt></p>
<p class="sidebar-title first"><tt class="literal"><span class="pre">const</span></tt> and an iterator's <tt class="literal"><span class="pre">value_type</span></tt></p>
<p>The C++ standard requires an iterator's <tt class="literal"><span class="pre">value_type</span></tt> <em>not</em> be
<tt class="literal"><span class="pre">const</span></tt>-qualified, so <tt class="literal"><span class="pre">iterator_facade</span></tt> strips the
<tt class="literal"><span class="pre">const</span></tt> from its <tt class="literal"><span class="pre">Value</span></tt> parameter in order to produce the

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doc/iterator_facade_ref.rst
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@ -15,7 +15,7 @@
, class Difference = ptrdiff_t
>
class iterator_facade {
public:
public:
typedef remove_const<Value>::type value_type;
typedef Reference reference;
typedef Value\* pointer;
@ -32,6 +32,8 @@
Derived& operator+=(difference_type n);
Derived& operator-=(difference_type n);
Derived operator-(difference_type n) const;
protected:
typedef iterator_facade iterator_facade\_;
};
// Comparison operators

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doc/new-iter-concepts.pdf
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5
include/boost/iterator/iterator_adaptor.hpp
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@ -247,10 +247,10 @@ namespace boost
{
friend class iterator_core_access;
protected:
typedef typename detail::iterator_adaptor_base<
Derived, Base, Value, Traversal, Reference, Difference
>::type super_t;
public:
iterator_adaptor() {}
@ -263,6 +263,9 @@ namespace boost
{ return m_iterator; }
protected:
// for convenience in derived classes
typedef iterator_adaptor<Derived,Base,Value,Traversal,Reference,Difference> iterator_adaptor_;
//
// lvalue access to the Base object for Derived
//

6
include/boost/iterator/iterator_facade.hpp
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@ -586,8 +586,6 @@ namespace boost
//
// Curiously Recurring Template interface.
//
typedef Derived derived_t;
Derived& derived()
{
return *static_cast<Derived*>(this);
@ -602,6 +600,10 @@ namespace boost
Value, CategoryOrTraversal, Reference, Difference
> associated_types;
protected:
// For use by derived classes
typedef iterator_facade<Derived,Value,Reference,Difference> iterator_facade_;
public:
typedef typename associated_types::value_type value_type;