Subject: [Boost-commit] svn:boost r78445 - in sandbox/type_erasure: boost/type_erasure libs/type_erasure/doc libs/type_erasure/example
From: steven_at_[hidden]
Date: 2012-05-12 21:53:53
Author: steven_watanabe
Date: 2012-05-12 21:53:52 EDT (Sat, 12 May 2012)
New Revision: 78445
URL: http://svn.boost.org/trac/boost/changeset/78445
Log:
Doc updates.
Added:
sandbox/type_erasure/libs/type_erasure/example/associated.cpp (contents, props changed)
Text files modified:
sandbox/type_erasure/boost/type_erasure/callable.hpp | 3 ++-
sandbox/type_erasure/boost/type_erasure/deduced.hpp | 2 +-
sandbox/type_erasure/boost/type_erasure/same_type.hpp | 9 +++++++++
sandbox/type_erasure/libs/type_erasure/doc/type_erasure.qbk | 19 ++++++++++++++++++-
sandbox/type_erasure/libs/type_erasure/example/Jamfile.jam | 1 +
5 files changed, 31 insertions(+), 3 deletions(-)
Modified: sandbox/type_erasure/boost/type_erasure/callable.hpp
==============================================================================
--- sandbox/type_erasure/boost/type_erasure/callable.hpp (original)
+++ sandbox/type_erasure/boost/type_erasure/callable.hpp 2012-05-12 21:53:52 EDT (Sat, 12 May 2012)
@@ -34,7 +34,8 @@
/**
* The @ref callable concept allows an @ref any to hold function objects.
- * @c Sig is interpreted in the same way as for Boost.Function.
+ * @c Sig is interpreted in the same way as for Boost.Function, except
+ * that the arguments and return type are allowed to be placeholders.
* @c F must be a @ref placeholder.
*
* Multiple instances of @ref callable can be used
Modified: sandbox/type_erasure/boost/type_erasure/deduced.hpp
==============================================================================
--- sandbox/type_erasure/boost/type_erasure/deduced.hpp (original)
+++ sandbox/type_erasure/boost/type_erasure/deduced.hpp 2012-05-12 21:53:52 EDT (Sat, 12 May 2012)
@@ -27,7 +27,7 @@
* in the arguments of the metafunction and then evaluating it.
*
* When using @ref deduced in a template context, if it is possible for
- * Metafunction to contain no placeholders, use the nested type,
+ * Metafunction to contain no placeholders at all, use the nested type,
* to automatically evaluate it early as needed.
*/
template<class Metafunction>
Modified: sandbox/type_erasure/boost/type_erasure/same_type.hpp
==============================================================================
--- sandbox/type_erasure/boost/type_erasure/same_type.hpp (original)
+++ sandbox/type_erasure/boost/type_erasure/same_type.hpp 2012-05-12 21:53:52 EDT (Sat, 12 May 2012)
@@ -18,6 +18,15 @@
* A built in concept that indicates that two
* types are the same. Either T or U or both
* can be placeholders.
+ *
+ * \warning Any number of instances of @ref deduced
+ * can be connected with @ref same_type, but there
+ * should be at most one regular placeholder in
+ * the group. same_type<_a, _b> is not allowed.
+ * The reason for this is that the library needs
+ * to normalize all the placeholders, and in this
+ * context there is no way to decide whether to
+ * use @ref _a or @ref _b.
*/
template<class T, class U>
struct same_type {};
Modified: sandbox/type_erasure/libs/type_erasure/doc/type_erasure.qbk
==============================================================================
--- sandbox/type_erasure/libs/type_erasure/doc/type_erasure.qbk (original)
+++ sandbox/type_erasure/libs/type_erasure/doc/type_erasure.qbk 2012-05-12 21:53:52 EDT (Sat, 12 May 2012)
@@ -24,6 +24,7 @@
[def __binding [classref boost::type_erasure::binding binding]]
[def __placeholder [classref boost::type_erasure::placeholder placeholder]]
[def __call [funcref boost::type_erasure::call call]]
+[def __deduced [classref boost::type_erasure::deduced deduced]]
[def __addable [classref boost::type_erasure::addable addable]]
[def __subtractable [classref boost::type_erasure::subtractable subtractable]]
@@ -56,6 +57,8 @@
[def __less_than_comparable [classref boost::type_erasure::less_than_comparable less_than_comparable]]
[def __ostreamable [classref boost::type_erasure::ostreamable ostreamable]]
[def __istreamable [classref boost::type_erasure::istreamable istreamable]]
+[def __forward_iterator [classref boost::type_erasure::forward_iterator forward_iterator]]
+[def __same_type [classref boost::type_erasure::same_type same_type]]
[section:introduction Introduction]
@@ -134,6 +137,11 @@
[overload]
[endsect]
+[section:overload Associated Types]
+[import ../example/associated.cpp]
+[associated]
+[endsect]
+
[endsect]
[section:examples Examples]
@@ -204,6 +212,16 @@
[[`operator[]`][__subscriptable`<R, T, N = std::ptrdiff_t>`][`R` should usually be a reference. `T` can be optionally const qualified.]]
]
+[table:iterator Iterator Concepts
+ [[concept][notes]]
+ [[__forward_iterator`<T>`][Use __same_type to control the iterator's value type.]]
+]
+
+[table:iterator Special Concepts
+ [[concept][notes]]
+ [[__same_type`<T>`][Indicates that two types are the same.]]
+]
+
[endsect]
[xinclude reference.xml]
@@ -281,7 +299,6 @@
* Allow more control over vtable layout.
* Attempt to reuse sub-tables in conversions.
* Allow "dynamic_cast".
-* Allow deduction of placeholder bindings.
* Use C++0x features. (Rvalue references and
variadic templates in particular.)
* Optimize the compile-time cost.
Modified: sandbox/type_erasure/libs/type_erasure/example/Jamfile.jam
==============================================================================
--- sandbox/type_erasure/libs/type_erasure/example/Jamfile.jam (original)
+++ sandbox/type_erasure/libs/type_erasure/example/Jamfile.jam 2012-05-12 21:53:52 EDT (Sat, 12 May 2012)
@@ -16,5 +16,6 @@
compile concept_map.cpp ;
compile compose.cpp ;
compile overload.cpp ;
+compile associated.cpp ;
run print_sequence.cpp ;
Added: sandbox/type_erasure/libs/type_erasure/example/associated.cpp
==============================================================================
--- (empty file)
+++ sandbox/type_erasure/libs/type_erasure/example/associated.cpp 2012-05-12 21:53:52 EDT (Sat, 12 May 2012)
@@ -0,0 +1,94 @@
+// Boost.TypeErasure library
+//
+// Copyright 2012 Steven Watanabe
+//
+// Distributed under the Boost Software License Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// $Id$
+
+#include <boost/type_erasure/any.hpp>
+#include <boost/type_erasure/any_cast.hpp>
+#include <boost/type_erasure/builtin.hpp>
+#include <boost/type_erasure/operators.hpp>
+#include <boost/type_erasure/deduced.hpp>
+#include <boost/type_erasure/same_type.hpp>
+#include <boost/pointee.hpp>
+#include <boost/mpl/vector.hpp>
+#include <iostream>
+
+namespace mpl = boost::mpl;
+using namespace boost::type_erasure;
+
+//[associated1
+/*`
+ Associated types are defined using the __deduced
+ template. __deduced is just like an ordinary
+ placeholder, except that the type that it binds
+ to is determined by calling a metafunction and
+ does not need to be specified explicitly.
+
+ For example, we can define a concept for
+ holding any iterator, raw pointer, or
+ smart pointer as follows:
+*/
+
+template<class T = _self>
+struct pointer :
+ mpl::vector<
+ copy_constructible<T>,
+ dereferenceable<deduced<boost::pointee<T> >&, T>
+ >
+{
+ typedef deduced<boost::pointee<T> > element_type;
+};
+
+//]
+
+void basic1() {
+ //[associated2
+ /*`
+ Now when we construct `x`, `pointer<>::element_type` is
+ deduced as `boost::pointee<int*>::type` which is `int`.
+ */
+ int i = 10;
+ any<
+ mpl::vector<
+ pointer<>,
+ typeid_<pointer<>::element_type>
+ >
+ > x(&i);
+ int j = boost::type_erasure::any_cast<int>(*x); // j == i
+ //]
+}
+
+void basic2() {
+ //[associated3
+ /*`
+ Referring to the full name of the associated type
+ can be cumbersome when it's used many times. Also,
+ sometimes we want to require that the associated
+ type be a specific type. Both of these can be
+ solved using the __same_type concept. Here we
+ create an any that can hold any pointer whose
+ element type is `int`.
+ */
+ int i = 10;
+ any<
+ mpl::vector<
+ pointer<>,
+ same_type<pointer<>::element_type, int>
+ >
+ > x(&i);
+ std::cout << *x << std::endl; // prints 10
+ //]
+}
+
+//[associated
+//` (For the source of the examples in this section see
+//` [@boost:/libs/type_erasure/example/associated.cpp associated.cpp])
+//` [associated1]
+//` [associated2]
+//` [associated3]
+//]