Subject: [Boost-commit] svn:boost r80452 - trunk/libs/utility
From: daniel.j.walker_at_[hidden]
Date: 2012-09-08 11:32:36
Author: djwalker
Date: 2012-09-08 11:32:35 EDT (Sat, 08 Sep 2012)
New Revision: 80452
URL: http://svn.boost.org/trac/boost/changeset/80452
Log:
reverting [80445] which is still under discussion on the mailing list
Text files modified:
trunk/libs/utility/utility.htm | 45 ----------------------------------------
1 files changed, 0 insertions(+), 45 deletions(-)
Modified: trunk/libs/utility/utility.htm
==============================================================================
--- trunk/libs/utility/utility.htm (original)
+++ trunk/libs/utility/utility.htm 2012-09-08 11:32:35 EDT (Sat, 08 Sep 2012)
@@ -230,51 +230,6 @@
>::type type; // type is int</pre>
</blockquote>
- <p>The <code>result</code> template must be specialized for every valid calling signature of the function object.
- If the <code>operator()</code> accepts arguments by (possibly <code>const</code>) reference and/or is <code>const</code>
- qualified, the <code>result</code> specialization must take this into account. Type traits
- and more generic specializations may help to reduce the number of <code>result</code> specializations. This way <code>result_of</code> users
- will be able to specify argument types exactly according to the function object call expression. For example:</p>
-
- <blockquote>
- <pre>struct functor {
- template<class> struct result;
-
- // Use template parameter F to match the function object. This will allow result deduction for both const and non-const functor.
- template<class F, class T>
- struct result<F(T)> {
- // When argument type is matched like above, remember that the type may be a (const-qualified) reference.
- // Use type traits to transform the argument type.
- typedef typename remove_cv<typename remove_reference<T>::type>::type argument_type;
- typedef argument_type type;
- };
-
- // The operator can be called on both const and non-const functor. The argument can be lvalue or rvalue.
- template<class T>
- T operator()(T const& x) const
- {
- return x;
- }
-};
-
-// All following result_of uses are valid and result in int
-typedef boost::result_of< functor(int) >::type type1; // the argument is rvalue
-functor f;
-type1 r1 = f(10);
-
-typedef boost::result_of< const functor(int) >::type type2; // the function object is const
-const functor cf;
-type2 r2 = cf(10);
-
-typedef boost::result_of< functor(int&) >::type type3; // the argument is lvalue
-int a = 10;
-type3 r3 = f(a);
-
-typedef boost::result_of< functor(int const&) >::type type4; // the argument is const lvalue
-const int ca = 10;
-type4 r4 = f(ca);</pre>
- </blockquote>
-
<p>Since <code>decltype</code> is a new language
feature recently standardized in C++11,
if you are writing a function object