|
Boost-Commit : |
From: dave_at_[hidden]
Date: 2007-11-04 22:54:21
Author: dave
Date: 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
New Revision: 40769
URL: http://svn.boost.org/trac/boost/changeset/40769
Log:
Updated Concept Check library documentation.
Changed BOOST_CONCEPT_WHERE to BOOST_CONCEPT_REQUIRES to be more
consistent with the current C++0x proposal, which now uses a
"requires" keyword in lieu of "where."
Factored GCC workarounds into the BOOST_CONCEPT_USAGE macro.
Text files modified:
trunk/boost/concept/usage.hpp | 17
trunk/boost/concept/where.hpp | 47 +-
trunk/boost/concept_check.hpp | 223 +------------
trunk/boost/graph/graph_concepts.hpp | 81 ----
trunk/libs/concept_check/bad_error_eg.cpp | 19
trunk/libs/concept_check/concept_check.htm | 614 ++++++++++++++++++++-------------------
trunk/libs/concept_check/concept_covering.htm | 241 +++++++-------
trunk/libs/concept_check/creating_concepts.htm | 259 +++++++++------
trunk/libs/concept_check/fake_sort.hpp | 2
trunk/libs/concept_check/implementation.htm | 237 +++++++-------
trunk/libs/concept_check/prog_with_concepts.htm | 184 +++++------
trunk/libs/concept_check/reference.htm | 519 +++++++++++++++++++--------------
trunk/libs/concept_check/using_concept_check.htm | 411 ++++++++++++--------------
13 files changed, 1374 insertions(+), 1480 deletions(-)
Modified: trunk/boost/concept/usage.hpp
==============================================================================
--- trunk/boost/concept/usage.hpp (original)
+++ trunk/boost/concept/usage.hpp 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -21,9 +21,20 @@
~usage_requirements() { ((Model*)0)->~Model(); }
};
-# define BOOST_CONCEPT_USAGE(model) \
- BOOST_CONCEPT_ASSERT((boost::concept::usage_requirements<model>)); \
- ~model()
+# if BOOST_WORKAROUND(__GNUC__, <= 3)
+
+# define BOOST_CONCEPT_USAGE(model) \
+ model(); /* at least 2.96 and 3.4.3 both need this :( */ \
+ BOOST_CONCEPT_ASSERT((boost::concept::usage_requirements<model>)); \
+ ~model()
+
+# else
+
+# define BOOST_CONCEPT_USAGE(model) \
+ BOOST_CONCEPT_ASSERT((boost::concept::usage_requirements<model>)); \
+ ~model()
+
+# endif
# endif
Modified: trunk/boost/concept/where.hpp
==============================================================================
--- trunk/boost/concept/where.hpp (original)
+++ trunk/boost/concept/where.hpp 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -1,8 +1,8 @@
// Copyright David Abrahams 2006. 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)
-#ifndef BOOST_CONCEPT_WHERE_DWA2006430_HPP
-# define BOOST_CONCEPT_WHERE_DWA2006430_HPP
+#ifndef BOOST_CONCEPT_REQUIRES_DWA2006430_HPP
+# define BOOST_CONCEPT_REQUIRES_DWA2006430_HPP
# include <boost/parameter/aux_/parenthesized_type.hpp>
# include <boost/concept/assert.hpp>
@@ -12,7 +12,7 @@
// Template for use in handwritten assertions
template <class Model, class More>
-struct where_ : More
+struct requires_ : More
{
# if BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
typedef typename More::type type;
@@ -23,41 +23,52 @@
// Template for use by macros, where models must be wrapped in parens.
// This isn't in namespace detail to keep extra cruft out of resulting
// error messages.
-template <class ModelFn, class More>
-struct _where_ : More
+template <class ModelFn>
+struct _requires_
+{
+ enum { value = 0 };
+ BOOST_CONCEPT_ASSERT_FN(ModelFn);
+};
+
+template <int check, class Result>
+struct Requires_ : ::boost::parameter::aux::unaryfunptr_arg_type<Result>
{
# if BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
- typedef typename More::type type;
+ typedef typename ::boost::parameter::aux::unaryfunptr_arg_type<Result>::type type;
# endif
- BOOST_CONCEPT_ASSERT_FN(ModelFn);
};
-#define BOOST_CONCEPT_WHERE_OPEN(r,data,t) ::boost::_where_<void(*)t,
-#define BOOST_CONCEPT_WHERE_CLOSE(r,data,t) >
+
+#define BOOST_CONCEPT_REQUIRES_(r,data,t) + (::boost::_requires_<void(*)t>::value)
#if defined(NDEBUG) || BOOST_WORKAROUND(BOOST_MSVC, < 1300)
-# define BOOST_CONCEPT_WHERE(models, result) \
+# define BOOST_CONCEPT_REQUIRES(models, result) \
typename ::boost::parameter::aux::unaryfunptr_arg_type<void(*)result>::type
#elif BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
// Same thing as below without the initial typename
-# define BOOST_CONCEPT_WHERE(models, result) \
- BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_WHERE_OPEN, ~, models) \
+# define BOOST_CONCEPT_REQUIRES(models, result) \
+ ::boost::Requires_< \
+ (0 BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_REQUIRES_, ~, models)), \
::boost::parameter::aux::unaryfunptr_arg_type<void(*)result> \
- BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_WHERE_CLOSE, ~, models)::type
+ >::type
#else
// This just ICEs on MSVC6 :(
-# define BOOST_CONCEPT_WHERE(models, result) \
- typename BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_WHERE_OPEN, ~, models) \
- ::boost::parameter::aux::unaryfunptr_arg_type<void(*)result> \
- BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_WHERE_CLOSE, ~, models)::type
+# define BOOST_CONCEPT_REQUIRES(models, result) \
+ typename ::boost::Requires_< \
+ (0 BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_REQUIRES_, ~, models)), \
+ void(*)result \
+ >::type
#endif
+// C++0x proposed syntax changed. This supports an older usage
+#define BOOST_CONCEPT_WHERE(models,result) BOOST_CONCEPT_REQUIRES(models,result)
+
} // namespace boost::concept_check
-#endif // BOOST_CONCEPT_WHERE_DWA2006430_HPP
+#endif // BOOST_CONCEPT_REQUIRES_DWA2006430_HPP
Modified: trunk/boost/concept_check.hpp
==============================================================================
--- trunk/boost/concept_check.hpp (original)
+++ trunk/boost/concept_check.hpp 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -62,9 +62,6 @@
//
BOOST_concept(Integer, (T))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Integer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(Integer)
{
x.error_type_must_be_an_integer_type();
@@ -90,9 +87,6 @@
# endif
BOOST_concept(SignedInteger,(T)) {
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- SignedInteger(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(SignedInteger) {
x.error_type_must_be_a_signed_integer_type();
}
@@ -110,9 +104,6 @@
# endif
BOOST_concept(UnsignedInteger,(T)) {
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- UnsignedInteger(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(UnsignedInteger) {
x.error_type_must_be_an_unsigned_integer_type();
}
@@ -135,9 +126,6 @@
BOOST_concept(DefaultConstructible,(TT))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- DefaultConstructible(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(DefaultConstructible) {
TT a; // require default constructor
ignore_unused_variable_warning(a);
@@ -146,13 +134,9 @@
BOOST_concept(Assignable,(TT))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Assignable(); // at least 2.96 and 3.4.3 both need this :(
-#endif
-
BOOST_CONCEPT_USAGE(Assignable) {
#if !defined(_ITERATOR_) // back_insert_iterator broken for VC++ STL
- a = a; // require assignment operator
+ a = a; // require assignment operator
#endif
const_constraints(a);
}
@@ -166,12 +150,9 @@
TT a;
};
+
BOOST_concept(CopyConstructible,(TT))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- CopyConstructible(); // at least 2.96 and 3.4.3 both need this :(
-#endif
-
BOOST_CONCEPT_USAGE(CopyConstructible) {
TT a(b); // require copy constructor
TT* ptr = &a; // require address of operator
@@ -191,10 +172,6 @@
// The SGI STL version of Assignable requires copy constructor and operator=
BOOST_concept(SGIAssignable,(TT))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- SGIAssignable(); // at least 2.96 and 3.4.3 both need this :(
-#endif
-
BOOST_CONCEPT_USAGE(SGIAssignable) {
TT b(a);
#if !defined(_ITERATOR_) // back_insert_iterator broken for VC++ STL
@@ -216,9 +193,6 @@
BOOST_concept(Convertible,(X)(Y))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Convertible(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(Convertible) {
Y y = x;
ignore_unused_variable_warning(y);
@@ -244,9 +218,6 @@
BOOST_concept(EqualityComparable,(TT))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- EqualityComparable(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(EqualityComparable) {
require_boolean_expr(a == b);
require_boolean_expr(a != b);
@@ -257,9 +228,6 @@
BOOST_concept(LessThanComparable,(TT))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- LessThanComparable(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(LessThanComparable) {
require_boolean_expr(a < b);
}
@@ -270,9 +238,6 @@
// This is equivalent to SGI STL's LessThanComparable.
BOOST_concept(Comparable,(TT))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Comparable(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(Comparable) {
require_boolean_expr(a < b);
require_boolean_expr(a > b);
@@ -283,18 +248,6 @@
TT a, b;
};
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
-#define BOOST_DEFINE_BINARY_PREDICATE_OP_CONSTRAINT(OP,NAME) \
- BOOST_concept(NAME, (First)(Second)) \
- { \
- NAME(); \
- BOOST_CONCEPT_USAGE(NAME) { (void)constraints_(); } \
- private: \
- bool constraints_() { return a OP b; } \
- First a; \
- Second b; \
- }
-#else
#define BOOST_DEFINE_BINARY_PREDICATE_OP_CONSTRAINT(OP,NAME) \
BOOST_concept(NAME, (First)(Second)) \
{ \
@@ -304,20 +257,7 @@
First a; \
Second b; \
}
-#endif
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
-#define BOOST_DEFINE_BINARY_OPERATOR_CONSTRAINT(OP,NAME) \
- BOOST_concept(NAME, (Ret)(First)(Second)) \
- { \
- NAME(); \
- BOOST_CONCEPT_USAGE(NAME) { (void)constraints_(); } \
- private: \
- Ret constraints_() { return a OP b; } \
- First a; \
- Second b; \
- }
-#else
#define BOOST_DEFINE_BINARY_OPERATOR_CONSTRAINT(OP,NAME) \
BOOST_concept(NAME, (Ret)(First)(Second)) \
{ \
@@ -327,7 +267,6 @@
First a; \
Second b; \
}
-#endif
BOOST_DEFINE_BINARY_PREDICATE_OP_CONSTRAINT(==, EqualOp);
BOOST_DEFINE_BINARY_PREDICATE_OP_CONSTRAINT(!=, NotEqualOp);
@@ -347,9 +286,6 @@
BOOST_concept(Generator,(Func)(Return))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Generator(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(Generator) { test(is_void<Return>()); }
private:
@@ -370,9 +306,6 @@
BOOST_concept(UnaryFunction,(Func)(Return)(Arg))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- UnaryFunction(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(UnaryFunction) { test(is_void<Return>()); }
private:
@@ -394,9 +327,6 @@
BOOST_concept(BinaryFunction,(Func)(Return)(First)(Second))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- BinaryFunction(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(BinaryFunction) { test(is_void<Return>()); }
private:
void test(boost::mpl::false_)
@@ -418,9 +348,6 @@
BOOST_concept(UnaryPredicate,(Func)(Arg))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- UnaryPredicate(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(UnaryPredicate) {
require_boolean_expr(f(arg)); // require operator() returning bool
}
@@ -431,9 +358,6 @@
BOOST_concept(BinaryPredicate,(Func)(First)(Second))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- BinaryPredicate(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(BinaryPredicate) {
require_boolean_expr(f(a, b)); // require operator() returning bool
}
@@ -447,9 +371,6 @@
BOOST_concept(Const_BinaryPredicate,(Func)(First)(Second))
: BinaryPredicate<Func, First, Second>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Const_BinaryPredicate(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(Const_BinaryPredicate) {
const_constraints(f);
}
@@ -468,9 +389,6 @@
{
typedef typename Func::result_type result_type;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- AdaptableGenerator(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(AdaptableGenerator)
{
BOOST_CONCEPT_ASSERT((Convertible<result_type, Return>));
@@ -483,9 +401,6 @@
typedef typename Func::argument_type argument_type;
typedef typename Func::result_type result_type;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- AdaptableUnaryFunction(); // at least 2.96 and 3.4.3 both need this :(
-#endif
~AdaptableUnaryFunction()
{
BOOST_CONCEPT_ASSERT((Convertible<result_type, Return>));
@@ -505,9 +420,6 @@
typedef typename Func::second_argument_type second_argument_type;
typedef typename Func::result_type result_type;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- AdaptableBinaryFunction(); // at least 2.96 and 3.4.3 both need this :(
-#endif
~AdaptableBinaryFunction()
{
BOOST_CONCEPT_ASSERT((Convertible<result_type, Return>));
@@ -520,18 +432,12 @@
: UnaryPredicate<Func, Arg>
, AdaptableUnaryFunction<Func, bool, Arg>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- AdaptablePredicate(); // at least 2.96 and 3.4.3 both need this :(
-#endif
};
BOOST_concept(AdaptableBinaryPredicate,(Func)(First)(Second))
: BinaryPredicate<Func, First, Second>
, AdaptableBinaryFunction<Func, bool, First, Second>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- AdaptableBinaryPredicate(); // at least 2.96 and 3.4.3 both need this :(
-#endif
};
//===========================================================================
@@ -547,10 +453,7 @@
typedef typename boost::detail::iterator_traits<TT>::pointer pointer;
typedef typename boost::detail::iterator_traits<TT>::iterator_category iterator_category;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- InputIterator(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~InputIterator()
+ BOOST_CONCEPT_USAGE(InputIterator)
{
BOOST_CONCEPT_ASSERT((SignedInteger<difference_type>));
BOOST_CONCEPT_ASSERT((Convertible<iterator_category, std::input_iterator_tag>));
@@ -567,10 +470,7 @@
BOOST_concept(OutputIterator,(TT)(ValueT))
: Assignable<TT>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- OutputIterator(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~OutputIterator() {
+ BOOST_CONCEPT_USAGE(OutputIterator) {
++i; // require preincrement operator
i++; // require postincrement operator
@@ -584,10 +484,7 @@
BOOST_concept(ForwardIterator,(TT))
: InputIterator<TT>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- ForwardIterator(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~ForwardIterator()
+ BOOST_CONCEPT_USAGE(ForwardIterator)
{
BOOST_CONCEPT_ASSERT((Convertible<
BOOST_DEDUCED_TYPENAME ForwardIterator::iterator_category
@@ -605,10 +502,7 @@
BOOST_concept(Mutable_ForwardIterator,(TT))
: ForwardIterator<TT>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Mutable_ForwardIterator(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~Mutable_ForwardIterator() {
+ BOOST_CONCEPT_USAGE(Mutable_ForwardIterator) {
*i++ = *i; // require postincrement and assignment
}
private:
@@ -618,10 +512,7 @@
BOOST_concept(BidirectionalIterator,(TT))
: ForwardIterator<TT>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- BidirectionalIterator(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~BidirectionalIterator()
+ BOOST_CONCEPT_USAGE(BidirectionalIterator)
{
BOOST_CONCEPT_ASSERT((Convertible<
BOOST_DEDUCED_TYPENAME BidirectionalIterator::iterator_category
@@ -639,10 +530,7 @@
: BidirectionalIterator<TT>
, Mutable_ForwardIterator<TT>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Mutable_BidirectionalIterator(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~Mutable_BidirectionalIterator()
+ BOOST_CONCEPT_USAGE(Mutable_BidirectionalIterator)
{
*i-- = *i; // require postdecrement and assignment
}
@@ -654,10 +542,7 @@
: BidirectionalIterator<TT>
, Comparable<TT>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- RandomAccessIterator(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~RandomAccessIterator()
+ BOOST_CONCEPT_USAGE(RandomAccessIterator)
{
BOOST_CONCEPT_ASSERT((Convertible<
BOOST_DEDUCED_TYPENAME BidirectionalIterator<TT>::iterator_category
@@ -682,10 +567,7 @@
: RandomAccessIterator<TT>
, Mutable_BidirectionalIterator<TT>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Mutable_RandomAccessIterator(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~Mutable_RandomAccessIterator()
+ BOOST_CONCEPT_USAGE(Mutable_RandomAccessIterator)
{
i[n] = *i; // require element access and assignment
}
@@ -707,10 +589,7 @@
typedef typename C::const_pointer const_pointer;
typedef typename C::const_iterator const_iterator;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Container(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~Container()
+ BOOST_CONCEPT_USAGE(Container)
{
BOOST_CONCEPT_ASSERT((InputIterator<const_iterator>));
const_constraints(c);
@@ -737,10 +616,7 @@
typedef typename C::iterator iterator;
typedef typename C::pointer pointer;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Mutable_Container(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~Mutable_Container()
+ BOOST_CONCEPT_USAGE(Mutable_Container)
{
BOOST_CONCEPT_ASSERT((
Assignable<typename Mutable_Container::value_type>));
@@ -760,10 +636,7 @@
BOOST_concept(ForwardContainer,(C))
: Container<C>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- ForwardContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~ForwardContainer()
+ BOOST_CONCEPT_USAGE(ForwardContainer)
{
BOOST_CONCEPT_ASSERT((
ForwardIterator<
@@ -776,10 +649,7 @@
: ForwardContainer<C>
, Mutable_Container<C>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Mutable_ForwardContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~Mutable_ForwardContainer()
+ BOOST_CONCEPT_USAGE(Mutable_ForwardContainer)
{
BOOST_CONCEPT_ASSERT((
Mutable_ForwardIterator<
@@ -795,10 +665,7 @@
C::const_reverse_iterator
const_reverse_iterator;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- ReversibleContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~ReversibleContainer()
+ BOOST_CONCEPT_USAGE(ReversibleContainer)
{
BOOST_CONCEPT_ASSERT((
BidirectionalIterator<
@@ -823,10 +690,7 @@
{
typedef typename C::reverse_iterator reverse_iterator;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Mutable_ReversibleContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~Mutable_ReversibleContainer()
+ BOOST_CONCEPT_USAGE(Mutable_ReversibleContainer)
{
typedef typename Mutable_ForwardContainer<C>::iterator iterator;
BOOST_CONCEPT_ASSERT((Mutable_BidirectionalIterator<iterator>));
@@ -845,10 +709,7 @@
typedef typename C::size_type size_type;
typedef typename C::const_reference const_reference;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- RandomAccessContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~RandomAccessContainer()
+ BOOST_CONCEPT_USAGE(RandomAccessContainer)
{
BOOST_CONCEPT_ASSERT((
RandomAccessIterator<
@@ -875,10 +736,7 @@
private:
typedef Mutable_RandomAccessContainer self;
public:
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Mutable_RandomAccessContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~Mutable_RandomAccessContainer()
+ BOOST_CONCEPT_USAGE(Mutable_RandomAccessContainer)
{
BOOST_CONCEPT_ASSERT((Mutable_RandomAccessIterator<typename self::iterator>));
BOOST_CONCEPT_ASSERT((Mutable_RandomAccessIterator<typename self::reverse_iterator>));
@@ -900,10 +758,7 @@
// ... so why aren't we following the standard? --DWA
, DefaultConstructible<S>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Sequence(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~Sequence()
+ BOOST_CONCEPT_USAGE(Sequence)
{
S
c(n),
@@ -940,10 +795,7 @@
BOOST_concept(FrontInsertionSequence,(S))
: Sequence<S>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- FrontInsertionSequence(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~FrontInsertionSequence()
+ BOOST_CONCEPT_USAGE(FrontInsertionSequence)
{
c.push_front(t);
c.pop_front();
@@ -956,10 +808,7 @@
BOOST_concept(BackInsertionSequence,(S))
: Sequence<S>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- BackInsertionSequence(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~BackInsertionSequence()
+ BOOST_CONCEPT_USAGE(BackInsertionSequence)
{
c.push_back(t);
c.pop_back();
@@ -986,10 +835,7 @@
typedef typename C::value_compare value_compare;
typedef typename C::iterator iterator;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- AssociativeContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~AssociativeContainer()
+ BOOST_CONCEPT_USAGE(AssociativeContainer)
{
i = c.find(k);
r = c.equal_range(k);
@@ -1025,10 +871,7 @@
BOOST_concept(UniqueAssociativeContainer,(C))
: AssociativeContainer<C>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- UniqueAssociativeContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~UniqueAssociativeContainer()
+ BOOST_CONCEPT_USAGE(UniqueAssociativeContainer)
{
C c(first, last);
@@ -1046,10 +889,7 @@
BOOST_concept(MultipleAssociativeContainer,(C))
: AssociativeContainer<C>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- MultipleAssociativeContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~MultipleAssociativeContainer()
+ BOOST_CONCEPT_USAGE(MultipleAssociativeContainer)
{
C c(first, last);
@@ -1068,10 +908,7 @@
BOOST_concept(SimpleAssociativeContainer,(C))
: AssociativeContainer<C>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- SimpleAssociativeContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~SimpleAssociativeContainer()
+ BOOST_CONCEPT_USAGE(SimpleAssociativeContainer)
{
typedef typename C::key_type key_type;
typedef typename C::value_type value_type;
@@ -1082,10 +919,7 @@
BOOST_concept(PairAssociativeContainer,(C))
: AssociativeContainer<C>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- PairAssociativeContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~PairAssociativeContainer()
+ BOOST_CONCEPT_USAGE(PairAssociativeContainer)
{
typedef typename C::key_type key_type;
typedef typename C::value_type value_type;
@@ -1099,10 +933,7 @@
: AssociativeContainer<C>
, ReversibleContainer<C>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- SortedAssociativeContainer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- ~SortedAssociativeContainer()
+ BOOST_CONCEPT_USAGE(SortedAssociativeContainer)
{
C
c(kc),
Modified: trunk/boost/graph/graph_concepts.hpp
==============================================================================
--- trunk/boost/graph/graph_concepts.hpp (original)
+++ trunk/boost/graph/graph_concepts.hpp 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -58,10 +58,6 @@
typedef typename graph_traits<G>::traversal_category
traversal_category;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Graph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
-
BOOST_CONCEPT_USAGE(Graph)
{
BOOST_CONCEPT_ASSERT((DefaultConstructible<vertex_descriptor>));
@@ -80,11 +76,7 @@
typedef typename graph_traits<G>::traversal_category
traversal_category;
-
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- IncidenceGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
-
+
BOOST_CONCEPT_USAGE(IncidenceGraph) {
BOOST_CONCEPT_ASSERT((MultiPassInputIterator<out_edge_iterator>));
BOOST_CONCEPT_ASSERT((DefaultConstructible<edge_descriptor>));
@@ -122,10 +114,6 @@
typedef typename graph_traits<G>::traversal_category
traversal_category;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- BidirectionalGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
-
BOOST_CONCEPT_USAGE(BidirectionalGraph) {
BOOST_CONCEPT_ASSERT((MultiPassInputIterator<in_edge_iterator>));
BOOST_CONCEPT_ASSERT((Convertible<traversal_category,
@@ -156,10 +144,6 @@
typedef typename graph_traits<G>::traversal_category
traversal_category;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- AdjacencyGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
-
BOOST_CONCEPT_USAGE(AdjacencyGraph) {
BOOST_CONCEPT_ASSERT((MultiPassInputIterator<adjacency_iterator>));
BOOST_CONCEPT_ASSERT((Convertible<traversal_category,
@@ -184,9 +168,7 @@
typedef typename graph_traits<G>::vertices_size_type vertices_size_type;
typedef typename graph_traits<G>::traversal_category
traversal_category;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- VertexListGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
+
BOOST_CONCEPT_USAGE(VertexListGraph) {
BOOST_CONCEPT_ASSERT((MultiPassInputIterator<vertex_iterator>));
BOOST_CONCEPT_ASSERT((Convertible<traversal_category,
@@ -232,9 +214,7 @@
typedef typename graph_traits<G>::edges_size_type edges_size_type;
typedef typename graph_traits<G>::traversal_category
traversal_category;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- EdgeListGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
+
BOOST_CONCEPT_USAGE(EdgeListGraph) {
BOOST_CONCEPT_ASSERT((MultiPassInputIterator<edge_iterator>));
BOOST_CONCEPT_ASSERT((DefaultConstructible<edge_descriptor>));
@@ -267,9 +247,6 @@
: VertexListGraph<G>
, EdgeListGraph<G>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- VertexAndEdgeListGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
};
// Where to put the requirement for this constructor?
@@ -280,9 +257,7 @@
BOOST_concept(EdgeMutableGraph,(G))
{
typedef typename graph_traits<G>::edge_descriptor edge_descriptor;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- EdgeMutableGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
+
BOOST_CONCEPT_USAGE(EdgeMutableGraph) {
p = add_edge(u, v, g);
remove_edge(u, v, g);
@@ -297,10 +272,8 @@
BOOST_concept(VertexMutableGraph,(G))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- VertexMutableGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
- BOOST_CONCEPT_USAGE(VertexMutableGraph) {
+
+ BOOST_CONCEPT_USAGE(VertexMutableGraph) {
v = add_vertex(g);
remove_vertex(v, g);
}
@@ -312,9 +285,6 @@
: EdgeMutableGraph<G>
, VertexMutableGraph<G>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- MutableGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
};
template <class edge_descriptor>
@@ -327,9 +297,6 @@
BOOST_concept(MutableIncidenceGraph,(G))
: MutableGraph<G>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- MutableIncidenceGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(MutableIncidenceGraph) {
remove_edge(iter, g);
remove_out_edge_if(u, p, g);
@@ -344,9 +311,6 @@
BOOST_concept(MutableBidirectionalGraph,(G))
: MutableIncidenceGraph<G>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- MutableBidirectionalGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(MutableBidirectionalGraph)
{
remove_in_edge_if(u, p, g);
@@ -360,9 +324,6 @@
BOOST_concept(MutableEdgeListGraph,(G))
: EdgeMutableGraph<G>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- MutableEdgeListGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(MutableEdgeListGraph) {
remove_edge_if(p, g);
}
@@ -374,9 +335,6 @@
BOOST_concept(VertexMutablePropertyGraph,(G))
: VertexMutableGraph<G>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- VertexMutablePropertyGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(VertexMutablePropertyGraph) {
v = add_vertex(vp, g);
}
@@ -389,9 +347,7 @@
: EdgeMutableGraph<G>
{
typedef typename graph_traits<G>::edge_descriptor edge_descriptor;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- EdgeMutablePropertyGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
+
BOOST_CONCEPT_USAGE(EdgeMutablePropertyGraph) {
p = add_edge(u, v, ep, g);
}
@@ -405,9 +361,7 @@
: Graph<G>
{
typedef typename graph_traits<G>::edge_descriptor edge_descriptor;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- AdjacencyMatrix(); // at least 2.96 and 3.4.3 both need this :(
-#endif
+
BOOST_CONCEPT_USAGE(AdjacencyMatrix) {
p = edge(u, v, g);
const_constraints(g);
@@ -425,9 +379,6 @@
{
typedef typename property_map<G, Property>::const_type const_Map;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- ReadablePropertyGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(ReadablePropertyGraph)
{
BOOST_CONCEPT_ASSERT((ReadablePropertyMapConcept<const_Map, X>));
@@ -448,9 +399,6 @@
: ReadablePropertyGraph<G, X, Property>
{
typedef typename property_map<G, Property>::type Map;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- PropertyGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(PropertyGraph) {
BOOST_CONCEPT_ASSERT((ReadWritePropertyMapConcept<Map, X>));
@@ -469,9 +417,7 @@
{
typedef typename property_map<G, Property>::type Map;
typedef typename property_map<G, Property>::const_type const_Map;
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- LvaluePropertyGraph(); // at least 2.96 and 3.4.3 both need this :(
-#endif
+
BOOST_CONCEPT_USAGE(LvaluePropertyGraph) {
BOOST_CONCEPT_ASSERT((LvaluePropertyMapConcept<const_Map, X>));
@@ -486,9 +432,6 @@
// This needs to move out of the graph library
BOOST_concept(Buffer,(B))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- Buffer(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(Buffer) {
b.push(t);
b.pop();
@@ -512,9 +455,6 @@
: EqualityComparable<C>
, DefaultConstructible<C>
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- ColorValue(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(ColorValue) {
c = color_traits<C>::white();
c = color_traits<C>::gray();
@@ -525,9 +465,6 @@
BOOST_concept(BasicMatrix,(M)(I)(V))
{
-#if BOOST_WORKAROUND(__GNUC__, <= 3)
- BasicMatrix(); // at least 2.96 and 3.4.3 both need this :(
-#endif
BOOST_CONCEPT_USAGE(BasicMatrix) {
V& elt = A[i][j];
const_constraints(A);
Modified: trunk/libs/concept_check/bad_error_eg.cpp
==============================================================================
--- trunk/libs/concept_check/bad_error_eg.cpp (original)
+++ trunk/libs/concept_check/bad_error_eg.cpp 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -1,13 +1,14 @@
+#include <vector>
+#include <complex>
+#include "algorithm"
+
+int main()
+{
+ std::vector<std::complex<float> > v;
+ std_::stable_sort(v.begin(), v.end());
+}
+
// (C) Copyright Jeremy Siek 2000.
// 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)
-
-#include <list>
-#include <algorithm>
-
-int main() {
- std::list<int> v;
- std::stable_sort(v.begin(), v.end());
- return 0;
-}
Modified: trunk/libs/concept_check/concept_check.htm
==============================================================================
--- trunk/libs/concept_check/concept_check.htm (original)
+++ trunk/libs/concept_check/concept_check.htm 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -1,312 +1,330 @@
-<HTML>
-<!--
- -- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000
- --
- -- Permission to use, copy, modify, distribute and sell this software
- -- and its documentation for any purpose is hereby granted without fee,
- -- provided that the above copyright notice appears in all copies and
- -- that both that copyright notice and this permission notice appear
- -- in supporting documentation. We make no
- -- representations about the suitability of this software for any
- -- purpose. It is provided "as is" without express or implied warranty.
- -->
-<Head>
-<Title>Concept Check Library</Title>
-</head>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+ "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+
+<html xmlns="http://www.w3.org/1999/xhtml">
+<!-- Copyright (c) 2000 Jeremy Siek and Andrew Lumsdaine, 2007 David Abrahams -->
+<!-- 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) -->
+
+<head>
+ <meta name="generator" content=
+ "HTML Tidy for Linux/x86 (vers 1 September 2005), see www.w3.org" />
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
-<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
- ALINK="#ff0000">
-<IMG SRC="../../boost.png"
- ALT="C++ Boost" width="277" height="86">
-
-<BR Clear>
-
-<H1>The Boost Concept Check Library (BCCL)</H1>
-
-<h2>
-<A NAME="sec:concept-checking"></A>
-header <a href="../../boost/concept_check.hpp">
-<tt>boost/concept_check.hpp</tt></a>
-<br>and <a href="../../boost/concept_archetype.hpp">
-<tt>boost/concept_archetype.hpp</tt></a>
-</h2>
-
-<p>
-Generic programming in C++ is characterized by the use of template
-parameters to represent abstract data types (or ``concepts'').
-However, the C++ language itself does not provide a mechanism for the
-writer of a class or function template to explicitly state what
-concept the user-supplied template argument should model (or conform
-to). The common practice is to name the template parameter after the
-required concept as a hint to the user and to state the concept
-requirements in the documentation. However, often times the
-requirements are vague, incorrect, or nonexistent, which is quite a
-problem for the user, since he or she will not know exactly what kind
-of input is expected by the template. Furthermore, the following
-problems occur:
-
-<ul>
- <li>Compiler error messages resulting from incorrect template
- arguments can be particularly difficult to decipher. Often times
- the error does not point to the location of the template
- call-site, but instead exposes the internals of the template, which
- the user should never have to see.</li>
-
- <li>The documented concept requirements may not fully <i>cover</i>
- the template, meaning the user could get a compiler error even
- though the supplied template arguments meet the documented
- requirements.</li>
-
- <li>The documented concept requirements may be too stringent,
- requiring more than is really needed by the template.</li>
-
- <li>The requirements are not explicitly stated in the code, which
- makes the code harder to understand. Also, the code may
- get out-of-sync with the documented requirements.</li>
-</ul>
-
-The Boost Concept Checking Library provides:
-
-<ul>
- <li>A mechanism for inserting compile-time checks of template
- parameters.</li>
-
- <li>A framework for specifying concept requirements though concept
- checking classes.</li>
-
- <li>A mechanism for verifying that concept requirements cover the template.</li>
-
- <li>A suite of concept checking classes and archetype classes that
- match the concept requirements in the C++ Standard Library.</li>
-</ul>
-
-The mechanisms use standard C++ and introduce no run-time
-overhead. The main cost of using the mechanism is in compile-time.
-
-<p>
-Any programmer writing class or function templates ought to make
-concept checking a normal part of their code writing routine. A
-concept check should be inserted for each template parameter in a
-component's public interface. If the concept is one of the ones from
-the Standard Library, then simply use the matching concept checking
-class in the BCCL. If not, then write a new concept checking class -
-after all, they are typically only a few lines long. For new concepts,
-a matching archetype class should also be created, which is a minimal
-skeleton-implementation of the concept
-
-<p>
-The documentation is organized into the following sections.
-
-<OL>
-<LI>Introduction</LI>
-<LI>Motivating Example</LI>
-<LI>History</LI>
-<LI>Publications</LI>
-<LI>Acknowledgements</LI>
-<LI>Using Concept Checks</LI>
-<LI>Creating Concept Checking Classes</LI>
-<LI>Concept Covering and Archetypes</LI>
-<LI>Programming With Concepts</LI>
-<LI>Implementation</LI>
-<LI>Reference</LI>
-</OL>
-
-<p>
-Jeremy Siek contributed
-this library. Beman Dawes
-managed the formal review.
-
-<h2><a name="introduction">Introduction</a></h2>
-
-A <i>concept</i> is a set of requirements (valid expressions,
-associated types, semantic invariants, complexity guarantees, etc.)
-that a type must fulfill to be correctly used as arguments in a call
-to a generic algorithm. In C++, concepts are represented by formal
-template parameters to function templates (generic algorithms).
-However, C++ has no explicit mechanism for representing concepts ---
-template parameters are merely placeholders. By convention, these
-parameters are given names corresponding to the concept that is
-required, but a C++ compiler does not enforce compliance to the
-concept when the template parameter is bound to an actual type.
-
-<p>
-Naturally, if a generic algorithm is invoked with a type that does not
-fulfill at least the syntactic requirements of the concept, a
-compile-time error will occur. However, this error will not <i>per
- se</i> reflect the fact that the type did not meet all of the
-requirements of the concept. Rather, the error may occur deep inside
-the instantiation hierarchy at the point where an expression is not
-valid for the type, or where a presumed associated type is not
-available. The resulting error messages are largely uninformative and
-basically impenetrable.
-
-<p>
-What is required is a mechanism for enforcing ``concept safety'' at
-(or close to) the point of instantiation. The Boost Concept Checking
-Library uses some standard C++ constructs to enforce early concept
-compliance and that provides more informative error messages upon
-non-compliance.
-
-<p>
-Note that this technique only addresses the syntactic
-requirements of concepts (the valid expressions and associated types).
-We do not address the semantic invariants or complexity guarantees,
-which are also part of concept requirements..
-
-<h2><a name="motivating-example">Motivating Example</a></h2>
-
-We present a simple example to illustrate incorrect usage of a
-template library and the resulting error messages. In the code below,
-the generic <tt>std::stable_sort()</tt> algorithm from the Standard
-Template Library (STL)[<a
-href="bibliography.htm#austern99:_gener_progr_stl">3</a>, <a
-href="bibliography.htm#IB-H965502">4</a>,<a
-href="bibliography.htm#stepa.lee-1994:the.s:TR">5</a>] is applied to
-a linked list.
+ <title>Concept Check Library</title>
+ <link rel="stylesheet" href="../../rst.css" type="text/css" />
+</head>
-<pre>
+<body bgcolor="#FFFFFF" link="#0000EE" text="#000000" vlink="#551A8B" alink=
+"#FF0000">
+ <img src="../../boost.png" alt="C++ Boost" width="277" height=
+ "86" /><br clear="none" />
+
+ <h1>The Boost Concept Check Library (BCCL)</h1>
+
+ <blockquote>
+ The Concept Check library allows one to add explicit statement and
+ checking of <a href=
+ "../../more/generic_programming.html#concept">concepts</a> in the style
+ of the <a href=
+ "http://www.generic-programming.org/languages/conceptcpp/specification/">proposed
+ C++ language extension</a>.
+ </blockquote>
+
+ <h2><a name="sec:concept-checking" id="sec:concept-checking"></a>Synopsis</a></h2>
+
+ <p>Generic programming in C++ is characterized by the use of template
+ parameters to represent abstract data types (or â<a href=
+ "../../more/generic_programming.html#concept">concepts</a>â). However, the
+ C++ language itself does not provide a mechanism for the writer of a class
+ or function template to explicitly state the concept that the user-supplied
+ template argument should model (or conform to). Template parameters are
+ commonly named after the concept they're required to model as a hint to the
+ user, and to make the concept requirements explicit in code. However, the
+ compiler doesn't treat these special names specially: a parameter named
+ <code>RandomAccessIterator</code> is no different to the compiler than one
+ named <code>T</code>. Furthermore,</p>
+
+ <ul>
+ <li>Compiler error messages resulting from incorrect template arguments
+ can be particularly difficult to decipher. Often times the error does not
+ point to the location of the template call-site, but instead exposes the
+ internals of the template, which the user should never have to see.</li>
+
+ <li>Without checking from the compiler, the documented requirements are
+ oftentimes vague, incorrect, or nonexistent, so a user cannot know
+ exactly what kind of arguments are expected.</li>
+
+ <li>The documented concept requirements may not fully <i>cover</i> the
+ needs of the actual template, meaning the user could get a compiler error
+ even though the supplied template arguments meet the documented
+ requirements.</li>
+
+ <li>The documented concept requirements may be too stringent, requiring
+ more than is really needed by the template.</li>
+
+ <li>Concept names in code may drift out-of-sync with the documented
+ requirements.</li>
+ </ul><p>The Boost Concept Checking Library provides:
+
+ <ul>
+ <li>A mechanism for inserting compile-time checks on template parameters
+ at their point of use.</li>
+
+ <li>A framework for specifying concept requirements though concept
+ checking classes.</li>
+
+ <li>A mechanism for verifying that concept requirements cover the
+ template.</li>
+
+ <li>A suite of concept checking classes and archetype classes that match
+ the concept requirements in the C++ Standard Library.</li>
+
+ <li>An alternative to the use of traits classes for accessing associated
+ types that mirrors the syntax proposed for the next C++ standard.</li>
+ </ul><p>The mechanisms use standard C++ and introduce no run-time overhead.
+ The main cost of using the mechanism is in compile-time.</p>
+
+ <p><strong>Every programmer writing class or function templates ought to
+ make concept checking a normal part of their code writing routine.</strong>
+ A concept check should be inserted for each template parameter in a
+ component's public interface. If the concept is one of the ones from the
+ Standard Library, then simply use the matching concept checking class in
+ the BCCL. If not, then write a new concept checking class - after all, they
+ are typically only a few lines long. For new concepts, a matching archetype
+ class should also be created, which is a minimal skeleton-implementation of
+ the concept</p>
+
+ <p>The documentation is organized into the following sections.</p>
+
+ <ol>
+ <li>Introduction</li>
+
+ <li>Motivating Example</li>
+
+ <li>History</li>
+
+ <li>Publications</li>
+
+ <li>Acknowledgements</li>
+
+ <li>Using Concept Checks</li>
+
+ <li><a href="creating_concepts.htm">Creating Concept Checking
+ Classes</a></li>
+
+ <li><a href="./concept_covering.htm">Concept Covering and
+ Archetypes</a></li>
+
+ <li>Programming With Concepts</li>
+
+ <li>Implementation</li>
+
+ <li>Reference</li>
+ </ol>
+
+ <p>Jeremy Siek contributed this
+ library. Beman Dawes managed
+ the formal review. <a href="../../people/dave_abrahams.htm">Dave
+ Abrahams</a> contributed a rewrite that updated syntax to be more
+ compatible with proposed syntax for concept support the C++ core
+ language.</p>
+
+ <h2><a name="introduction" id="introduction">Introduction</a></h2><p>A
+ <i>concept</i> is a set of requirements (valid expressions, associated
+ types, semantic invariants, complexity guarantees, etc.) that a type must
+ fulfill to be correctly used as arguments in a call to a generic algorithm.
+ In C++, concepts are represented by formal template parameters to function
+ templates (generic algorithms). However, C++ has no explicit mechanism for
+ representing conceptsâtemplate parameters are merely placeholders. By
+ convention, these parameters are given names corresponding to the concept
+ that is required, but a C++ compiler does not enforce compliance to the
+ concept when the template parameter is bound to an actual type.
+
+ <p>Naturally, if a generic algorithm is invoked with a type that does not
+ fulfill at least the syntactic requirements of the concept, a compile-time
+ error will occur. However, this error will not <i>per se</i> reflect the
+ fact that the type did not meet all of the requirements of the concept.
+ Rather, the error may occur deep inside the instantiation hierarchy at the
+ point where an expression is not valid for the type, or where a presumed
+ associated type is not available. The resulting error messages are largely
+ uninformative and basically impenetrable.</p>
+
+ <p>What is required is a mechanism for enforcing
+ âconcept safetyâ at (or close to) the point
+ of instantiation. The Boost Concept Checking Library uses some standard C++
+ constructs to enforce early concept compliance and that provides more
+ informative error messages upon non-compliance.</p>
+
+ <p>Note that this technique only addresses the syntactic requirements of
+ concepts (the valid expressions and associated types). We do not address
+ the semantic invariants or complexity guarantees, which are also part of
+ concept requirements..</p>
+
+ <h2><a name="motivating-example" id="motivating-example">Motivating
+ Example</a></h2>
+
+ <p>We present a simple example to illustrate incorrect usage of a template
+ library and the resulting error messages. In the code below, the generic
+ <tt>std::stable_sort()</tt> algorithm from the Standard Template Library
+ (STL)[3, <a href=
+ "bibliography.htm#IB-H965502">4</a>,<a href=
+ "bibliography.htm#stepa.lee-1994:the.s:TR">5</a>] is applied to a linked
+ list.</p>
+ <pre>
<a href="./bad_error_eg.cpp">bad_error_eg.cpp</a>:
- 1 #include <list>
- 2 #include <algorithm>
- 3
- 4 int main(int, char*[]) {
- 5 std::list<int> v;
- 6 std::stable_sort(v.begin(), v.end());
- 7 return 0;
- 8 }
+<font color="gray">1</font> #include <vector>
+<font color="gray">2</font color="gray"> #include <complex>
+<font color="gray">3</font color="gray"> #include <algorithm>
+<font color="gray">4</font color="gray">
+<font color="gray">5</font color="gray"> int main()
+<font color="gray">6</font color="gray"> {
+<font color="gray">7</font color="gray"> std::vector<std::complex<float> > v;
+<font color="gray">8</font color="gray"> std::stable_sort(v.begin(), v.end());
+<font color="gray">9</font color="gray"> }
</pre>
-Here, the
-<tt>std::stable_sort()</tt> algorithm is prototyped as follows:
-<pre>
+ <p>Here, the <tt>std::stable_sort()</tt> algorithm is prototyped as
+ follows:</p>
+ <pre>
template <class RandomAccessIterator>
void stable_sort(RandomAccessIterator first, RandomAccessIterator last);
</pre>
-Attempting to compile this code with Gnu C++ produces the following
-compiler error. The output from other compilers is listed in the
-Appendix.
-
-<pre>
-stl_algo.h: In function `void __merge_sort_loop<_List_iterator
- <int,int &,int *>, int *, int>(_List_iterator<int,int &,int *>,
- _List_iterator<int,int &,int *>, int *, int)':
-stl_algo.h:1448: instantiated from `__merge_sort_with_buffer
- <_List_iterator<int,int &,int *>, int *, int>(
- _List_iterator<int,int &,int *>, _List_iterator<int,int &,int *>,
- int *, int *)'
-stl_algo.h:1485: instantiated from `__stable_sort_adaptive<
- _List_iterator<int,int &,int *>, int *, int>(_List_iterator
- <int,int &,int *>, _List_iterator<int,int &,int *>, int *, int)'
-stl_algo.h:1524: instantiated from here
-stl_algo.h:1377: no match for `_List_iterator<int,int &,int *> & -
- _List_iterator<int,int &,int *> &'
+ <p>Attempting to compile this code with Gnu C++ produces the following
+ compiler error:</p>
+ <pre>
+/usr/include/c++/4.1.2/bits/stl_algo.h: In function âvoid std::
+ __insertion_sort(_RandomAccessIterator, _RandomAccessIterator) [with
+ _RandomAccessIterator = __gnu_cxx::__normal_iterator<std::complex<float
+ >*, std::vector<std::complex<float>, std::allocator<std::complex<
+ float> > > >]â:
+/usr/include/c++/4.1.2/bits/stl_algo.h:3066: instantiated from âvoid
+ std::__inplace_stable_sort(_RandomAccessIterator,
+ _RandomAccessIterator) [with _RandomAccessIterator = __gnu_cxx::
+ __normal_iterator<std::complex<float>*, std::vector<std::complex<
+ float>, std::allocator<std::complex<float> > > >]â
+/usr/include/c++/4.1.2/bits/stl_algo.h:3776: instantiated from âvoid
+ std::stable_sort(_RandomAccessIterator, _RandomAccessIterator) [with
+ _RandomAccessIterator = __gnu_cxx::__normal_iterator<std::complex<float
+ >*, std::vector<std::complex<float>, std::allocator<std::complex<
+ float> > > >]â
+bad_error_eg.cpp:8: instantiated from here
+/usr/include/c++/4.1.2/bits/stl_algo.h:2277: error: no match for
+ âoperator<â in â__val < __first. __gnu_cxx::__normal_iterator<
+ _Iterator, _Container>::operator* [with _Iterator = std::complex<float
+ >*, _Container = std::vector<std::complex<float>, std::allocator<
+ std::complex<float> > >]()â
</pre>
-In this case, the fundamental error is that
-<tt>std:list::iterator</tt> does not model the concept of <a
-href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">
-RandomAccessIterator</a>. The list iterator is only bidirectional, not
-fully random access (as would be a vector iterator). Unfortunately,
-there is nothing in the error message to indicate this to the user.
-
-<p>
-To a C++ programmer having enough experience with template libraries
-the error may be obvious. However, for the uninitiated, there are several
-reasons why this message would be hard to understand.
-
-<OL>
- <LI> The location of the error, line 6 of <tt>bad_error_eg.cpp</tt>
- is not pointed to by the error message, despite the fact that Gnu C++
- prints up to 4 levels deep in the instantiation stack.
- <LI> There is no textual correlation between the error message and the
- documented requirements for <tt>std::stable_sort()</tt> and for
- <a
-href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">
-RandomAccessIterator</a>.
- <LI> The error message is overly long, listing functions internal
- to the STL that the user does not (and should not!) know or care
- about.
- <LI> With so many internal library functions listed in the error
- message, the programmer could easily infer that the error is due
- to the library, rather than to his or her own code.
-</OL>
-
-The following is an example of what we might expect from a more
-informative message (and is in fact what the Boost Concept Checking
-Library produces):
-
-<pre>
-boost/concept_check.hpp: In method `void LessThanComparableConcept
- <_List_iterator<int,int &,int *> >::~LessThanComparableConcept()':
-boost/concept_check.hpp:334: instantiated from `RandomAccessIteratorConcept
- <_List_iterator<int,int &,int *> >::~RandomAccessIteratorConcept()'
-bad_error_eg.cpp:6: instantiated from `stable_sort<_List_iterator
- <int,int &,int *> >(_List_iterator<int,int &,int *>,
- _List_iterator<int,int &,int *>)'
-boost/concept_check.hpp:209: no match for `_List_iterator<int,int &,int *> &
- < _List_iterator<int,int &,int *> &'
+ <p>In this case, the fundamental error is
+ that <tt>std:complex<float></tt> does not model the <a href=
+ "http://www.sgi.com/tech/stl/LessThanComparable.html">LessThanComparable</a>
+ concept. Unfortunately, there is nothing in the error message to
+ indicate that to the user.</p>
+
+ <p>The error may be obvious to a C++ programmer having enough
+ experience with template libraries, but there are several reasons
+ why this message could be hard for the uninitiated to
+ understand:</p>
+
+ <ol>
+ <li>There is no textual correlation between the error message and the
+ documented requirements for <tt>std::stable_sort()</tt> and for <a href=
+ "http://www.sgi.com/tech/stl/LessThanComparable.html">LessThanComparable</a>.</li>
+
+ <li>The error message is overly long, listing functions internal
+ to the STL (e.g. <code>__insertion_sort</code>) that the user
+ does not (and should not!) know or care about.</li>
+
+ <li>With so many internal library functions listed in the error message,
+ the programmer could easily infer that the problem is in the library,
+ rather than in his or her own code.</li>
+ </ol>
+
+ <p>The following is an example of what we might expect from a more
+ informative message (and is in fact what the Boost Concept Checking Library
+ produces):</p>
+ <pre>
+boost/concept_check.hpp: In destructor âboost::LessThanComparable<TT>::~
+ LessThanComparable() [with TT = std::complex<float>]â:
+boost/concept/detail/general.hpp:29: instantiated from âstatic void boost::
+ concept::requirement<Model>::failed() [with Model = boost::
+ LessThanComparable<std::complex<float> >]â
+boost/concept/requires.hpp:30: instantiated from âboost::_requires_<void
+ (*)(boost::LessThanComparable<std::complex<float> >)>â
+bad_error_eg.cpp:8: instantiated from here
+boost/concept_check.hpp:236: error: no match for âoperator<â in â((boost::
+ LessThanComparable<std::complex<float> >*)this)->boost::
+ LessThanComparable<std::complex<float> >::a < ((boost::
+ LessThanComparable<std::complex<float> >*)this)->boost::
+ LessThanComparable<std::complex<float> >::bâ
</pre>
-This message rectifies several of the shortcomings of the standard
-error messages.
-
-<UL>
-<LI> The location of the error, <tt>bad_error_eg.cpp:6</tt> is
- specified in the error message.
-<LI> The message refers explicitly to concepts that the user can look
- up in the STL documentation (<a
-href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">
-RandomAccessIterator</a>).
-<LI> The error message is now much shorter and does not reveal
- internal STL functions.
-<LI> The presence of <tt>concept_check.hpp</tt> in the error message
- alerts the user to the fact that the error lies in the user code and
- not in the library implementation.
-</UL>
-
-<h2><a name="history">History</a></h2>
-
-An earlier version of this concept checking system was developed by
-the author while working at SGI in their C++ compiler and library
-group. The earlier version is now part of the SGI STL distribution. The
-boost concept checking library differs from the concept checking in
-the SGI STL in that the definition of concept checking classes has
-been greatly simplified, at the price of less helpful verbiage in the
-error messages.
-
-<h2><a name="publications">Publications</a></h2>
-
-<ul>
- <li><a href="http://www.oonumerics.org/tmpw00/">
- C++ Template Workshop 2000</a>, Concept Checking</li>
-</ul>
-
-<h2><a name="acknowledgements">Acknowledgements</a></h2>
-
-The idea to use function pointers to cause instantiation is due to
-Alexander Stepanov. I am not sure of the origin of the idea to use
-expressions to do up-front checking of templates, but it did appear in
-D&E[
-2].
-Thanks to Matt Austern for his excellent documentation and
-organization of the STL concepts, upon which these concept checks
-are based. Thanks to Boost members for helpful comments and
-reviews.
-
-
-<p>
-Next: Using Concept Checks
-
-<br>
-<HR>
-<TABLE>
-<TR valign=top>
-<TD nowrap>Copyright © 2000</TD><TD>
-Jeremy Siek(<A
-HREF="mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</A>)
-Andrew Lumsdaine</A>(<A HREF="mailto:lums_at_[hidden]">lums_at_[hidden]</A>)
-</TD></TR></TABLE>
+ <p>This message rectifies several of the shortcomings of the standard error
+ messages.</p>
-</BODY>
-</HTML>
+ <ul>
+ <li>The message refers explicitly to concepts that the user can look up
+ in the STL documentation (<a href=
+ "http://www.sgi.com/tech/stl/LessThanComparable.html">LessThanComparable</a>).</li>
+
+ <li>The error message is now much shorter and does not reveal
+ internal STL functions, nor indeed does it even point
+ to <code>std::stable_sort</code>.</li>
+
+ <li>The presence of <tt>concept_check.hpp</tt> in the error message
+ alerts the user to the fact that the error lies in the user code and not
+ in the library implementation.</li>
+ </ul>
+
+ <h2><a name="history" id="history">History</a></h2>
+
+ <p>The first version of this concept checking system was developed
+ by Jeremy Siek while working at SGI in their C++ compiler and
+ library group. That version is now part of the SGI STL
+ distribution. The system originally introduced as the boost concept
+ checking library differs from concept checking in the SGI STL in
+ that the definition of concept checking classes was greatly
+ simplified, at the price of less helpful verbiage in the error
+ messages. In 2006 the system was rewritten (preserving backward
+ compatibility) by Dave Abrahams to be easier to use, more similar to
+ the proposed concept support the C++ core language, and to give
+ better error messages.
+</p>
+
+ <h2><a name="publications" id="publications">Publications</a></h2>
+
+ <ul>
+ <li><a href="http://www.oonumerics.org/tmpw00/">C++ Template Workshop
+ 2000</a>, Concept Checking</li>
+ </ul>
+
+ <h2><a name="acknowledgements" id=
+ "acknowledgements">Acknowledgements</a></h2><p>The idea to use function
+ pointers to cause instantiation is due to Alexander Stepanov. We are not sure
+ of the origin of the idea to use expressions to do up-front checking of
+ templates, but it did appear in D&E[ <a href=
+ "bibliography.htm#stroustrup94:_design_evolution">2</a>]. Thanks to Matt
+ Austern for his excellent documentation and organization of the STL
+ concepts, upon which these concept checks are based. Thanks to Boost
+ members for helpful comments and reviews.
+
+ <p><a href="./using_concept_check.htm">Next: Using Concept
+ Checks</a><br /></p>
+ <hr />
+
+ <table>
+ <tr valign="top">
+ <td nowrap="nowrap">Copyright © 2000</td>
+
+ <td>Jeremy Siek(<a href=
+ "mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</a>) Andrew
+ Lumsdaine(<a href="mailto:lums_at_[hidden]">lums_at_[hidden]</a>),
+ 2007 <a href="mailto:dave_at_[hidden]">David Abrahams</a>.
+</td>
+ </tr>
+ </table>
+</body>
+</html>
Modified: trunk/libs/concept_check/concept_covering.htm
==============================================================================
--- trunk/libs/concept_check/concept_covering.htm (original)
+++ trunk/libs/concept_check/concept_covering.htm 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -1,126 +1,125 @@
-<HTML>
-<!--
- -- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000
- --
- -- Permission to use, copy, modify, distribute and sell this software
- -- and its documentation for any purpose is hereby granted without fee,
- -- provided that the above copyright notice appears in all copies and
- -- that both that copyright notice and this permission notice appear
- -- in supporting documentation. We make no
- -- representations about the suitability of this software for any
- -- purpose. It is provided "as is" without express or implied warranty.
- -->
-<Head>
-<Title>Concept Covering and Archetypes</Title>
-<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
- ALINK="#ff0000">
-<IMG SRC="../../boost.png"
- ALT="C++ Boost" width="277" height="86">
-
-<BR Clear>
-
-<h2><a name="concept-covering">Concept Covering and Archetypes</a></h2>
-
-We have discussed how it is important to select the minimal
-requirements (concepts) for the inputs to a component, but it is
-equally important to verify that the chosen concepts <i>cover</i> the
-algorithm. That is, any possible user error should be caught by the
-concept checks and not let slip through. Concept coverage can be
-verified through the use of <i>archetype classes</i>. An archetype
-class is an exact implementation of the interface associated with a
-particular concept. The run-time behavior of the archetype class is
-not important, the functions can be left empty. A simple test program
-can then be compiled with the archetype classes as the inputs to the
-component. If the program compiles then one can be sure that the
-concepts cover the component.
-
-The following code shows the archetype class for the <a
-href="http://www.sgi.com/tech/stl/InputIterator.html">Input
-Iterator</a> concept. Some care must be taken to ensure that the
-archetype is an exact match to the concept. For example, the concept
-states that the return type of <tt>operator*()</tt> must be
-convertible to the value type. It does not state the more stringent
-requirement that the return type be <tt>T&</tt> or <tt>const
-T&</tt>. That means it would be a mistake to use <tt>T&</tt>
-or <tt>const T&</tt> for the return type of the archetype
-class. The correct approach is to create an artificial return type
-that is convertible to <tt>T</tt>, as we have done here with
-<tt>reference</tt>. The validity of the archetype class test is
-completely dependent on it being an exact match with the concept,
-which must be verified by careful (manual) inspection.
-
-<pre>
- template <class T>
- class input_iterator_archetype
- {
- private:
- typedef input_iterator_archetype self;
- public:
- typedef std::input_iterator_tag iterator_category;
- typedef T value_type;
- struct reference {
- operator const value_type&() const { return static_object<T>::get(); }
- };
- typedef const T* pointer;
- typedef std::ptrdiff_t difference_type;
- self& operator=(const self&) { return *this; }
- bool operator==(const self&) const { return true; }
- bool operator!=(const self&) const { return true; }
- reference operator*() const { return reference(); }
- self& operator++() { return *this; }
- self operator++(int) { return *this; }
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+ "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+
+<html xmlns="http://www.w3.org/1999/xhtml">
+<!-- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000 -->
+<!-- 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) -->
+
+<head>
+ <meta name="generator" content=
+ "HTML Tidy for Linux/x86 (vers 1 September 2005), see www.w3.org" />
+
+ <title>Concept Covering and Archetypes</title>
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+ <link rel="stylesheet" href="../../rst.css" type="text/css" />
+</head>
+
+<body bgcolor="#FFFFFF" link="#0000EE" text="#000000" vlink="#551A8B" alink=
+"#FF0000">
+ <img src="../../boost.png" alt="C++ Boost" width="277" height=
+ "86" /><br clear="none" />
+
+ <h2><a name="concept-covering" id="concept-covering">Concept Covering and
+ Archetypes</a></h2>
+
+ <p>We have discussed how it is important to select the minimal requirements
+ (concepts) for the inputs to a component, but it is equally important to
+ verify that the chosen concepts <i>cover</i> the algorithm. That is, any
+ possible user error should be caught by the concept checks and not let slip
+ through. Concept coverage can be verified through the use of <i>archetype
+ classes</i>. An archetype class is an exact implementation of the interface
+ associated with a particular concept. The run-time behavior of the
+ archetype class is not important, the functions can be left empty. A simple
+ test program can then be compiled with the archetype classes as the inputs
+ to the component. If the program compiles then one can be sure that the
+ concepts cover the component. The following code shows the archetype class
+ for the <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input
+ Iterator</a> concept. Some care must be taken to ensure that the archetype
+ is an exact match to the concept. For example, the concept states that the
+ return type of <tt>operator*()</tt> must be convertible to the value type.
+ It does not state the more stringent requirement that the return type be
+ <tt>T&</tt> or <tt>const T&</tt>. That means it would be a mistake
+ to use <tt>T&</tt> or <tt>const T&</tt> for the return type of the
+ archetype class. The correct approach is to create an artificial return
+ type that is convertible to <tt>T</tt>, as we have done here with
+ <tt>reference</tt>. The validity of the archetype class test is completely
+ dependent on it being an exact match with the concept, which must be
+ verified by careful (manual) inspection.</p>
+ <pre>
+template <class T>
+class input_iterator_archetype
+{
+private:
+ typedef input_iterator_archetype self;
+public:
+ typedef std::input_iterator_tag iterator_category;
+ typedef T value_type;
+ struct reference {
+ operator const value_type&() const { return static_object<T>::get(); }
};
+ typedef const T* pointer;
+ typedef std::ptrdiff_t difference_type;
+ self& operator=(const self&) { return *this; }
+ bool operator==(const self&) const { return true; }
+ bool operator!=(const self&) const { return true; }
+ reference operator*() const { return reference(); }
+ self& operator++() { return *this; }
+ self operator++(int) { return *this; }
+};
</pre>
-Generic algorithms are often tested by being instantiated with a
-number of common input types. For example, one might apply
-<tt>std::stable_sort()</tt> with basic pointer types as the iterators.
-Though appropriate for testing the run-time behavior of the algorithm,
-this is not helpful for ensuring concept coverage because C++ types
-never match particular concepts, they often provide much more than the
-minimal functionality required by any one concept. That is, even
-though the function template compiles with a given type, the concept
-requirements may still fall short of covering the functions actual
-requirements. This is why it is important to compile with archetype
-classes in addition to testing with common input types.
-
-<p>
-The following is an excerpt from <a
-href="./stl_concept_covering.cpp"><tt>stl_concept_covering.cpp</tt></a>
-that shows how archetypes can be used to check the requirement
-documentation for
-<a href="http://www.sgi.com/tech/stl/stable_sort.html">
-<tt>std::stable_sort()</tt></a>. In this case, it looks like the <a
-href="../utility/CopyConstructible.html">CopyConstructible</a> and <a
-href="../utility/Assignable.html">Assignable</a> requirements were
-forgotten in the SGI STL documentation (try removing those
-archetypes). The Boost archetype classes have been designed so that
-they can be layered. In this example the value type of the iterator
-is composed out of three archetypes. In the archetype class reference
-below, template parameters named <tt>Base</tt> indicate where the
-layered archetype can be used.
-
-<pre>
- {
- typedef less_than_comparable_archetype<
- sgi_assignable_archetype<> > ValueType;
- random_access_iterator_archetype<ValueType> ri;
- std::stable_sort(ri, ri);
- }
+ <p>Generic algorithms are often tested by being instantiated with a number
+ of common input types. For example, one might apply
+ <tt>std::stable_sort()</tt> with basic pointer types as the iterators.
+ Though appropriate for testing the run-time behavior of the algorithm, this
+ is not helpful for ensuring concept coverage because C++ types never match
+ particular concepts exactly. Instead, they often provide more than the
+ minimal functionality required by any one concept. Even though the function
+ template has concept checks, and compiles with a given type, the checks may
+ still fall short of covering all the functionality that is actually used.
+ This is why it is important to compile with archetype classes in addition
+ to testing with common input types.</p>
+
+ <p>The following is an excerpt from <a href=
+ "./stl_concept_covering.cpp"><tt>stl_concept_covering.cpp</tt></a> that
+ shows how archetypes can be used to check the requirement documentation for
+ <a href=
+ "http://www.sgi.com/tech/stl/stable_sort.html"><tt>std::stable_sort()</tt></a>.
+ In this case, it looks like the <a href=
+ "../utility/CopyConstructible.html">CopyConstructible</a> and <a href=
+ "../utility/Assignable.html">Assignable</a> requirements were forgotten in
+ the SGI STL documentation (try removing those archetypes). The Boost
+ archetype classes have been designed so that they can be layered. In this
+ example the value type of the iterator is composed out of three archetypes.
+ In the <a href="reference.htm#basic-archetype">archetype class
+ reference</a>, template parameters named <tt>Base</tt> indicate where the
+ layered archetype paradigm can be used.</p>
+ <pre>
+{
+ typedef less_than_comparable_archetype<
+ sgi_assignable_archetype<> > ValueType;
+ random_access_iterator_archetype<ValueType> ri;
+ std::stable_sort(ri, ri);
+}
</pre>
-Next: Programming with Concepts<br>
-Prev: Creating Concept Checking Classes
-
-<br>
-<HR>
-<TABLE>
-<TR valign=top>
-<TD nowrap>Copyright © 2000</TD><TD>
-Jeremy Siek(<A
-HREF="mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</A>)
-Andrew Lumsdaine</A>(<A HREF="mailto:lums_at_[hidden]">lums_at_[hidden]</A>)
-</TD></TR></TABLE>
-
-</BODY>
-</HTML>
+ <p><a href="./prog_with_concepts.htm">Next: Programming with
+ Concepts</a><br />
+ <a href="./creating_concepts.htm">Prev: Creating Concept Checking
+ Classes</a><br />
+ <hr />
+
+ <table>
+ <tr valign="top">
+ <td nowrap="nowrap">Copyright © 2000</td>
+
+ <td>Jeremy Siek(<a href=
+ "mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</a>) Andrew
+ Lumsdaine(<a href="mailto:lums_at_[hidden]">lums_at_[hidden]</a>),
+ 2007 <a href="mailto:dave_at_[hidden]">David Abrahams</a>.
+ </tr>
+ </table>
+</body>
+</html>
Modified: trunk/libs/concept_check/creating_concepts.htm
==============================================================================
--- trunk/libs/concept_check/creating_concepts.htm (original)
+++ trunk/libs/concept_check/creating_concepts.htm 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -1,110 +1,157 @@
-<HTML>
-<!--
- -- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000
- --
- -- Permission to use, copy, modify, distribute and sell this software
- -- and its documentation for any purpose is hereby granted without fee,
- -- provided that the above copyright notice appears in all copies and
- -- that both that copyright notice and this permission notice appear
- -- in supporting documentation. We make no
- -- representations about the suitability of this software for any
- -- purpose. It is provided "as is" without express or implied warranty.
- -->
-<Head>
-<Title>Creating Concept Checking Classes</Title>
-<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
- ALINK="#ff0000">
-<IMG SRC="../../boost.png"
- ALT="C++ Boost" width="277" height="86">
-
-<BR Clear>
-
-
-<h2><a name="creating-concept-checks">Creating Concept Checking Classes</a></h2>
-
-As an example of how to create a concept checking class, we look
-at how to create the corresponding checks for the
-<a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">
-RandomAccessIterator</a> concept. First, as a convention we name the
-concept checking class after the concept, and add the suffix
-``<tt>Concept</tt>''. Next we must define a member function named
-<tt>constraints()</tt> in which we will exercise the valid expressions
-of the concept. <tt>function_requires()</tt> expects this function's
-signature to appear exactly as it is appears below: a <tt>void</tt>
-non-const member function with no parameters.
-
-<p>
-The first part of the <tt>constraints()</tt> function includes
-the requirements that correspond to the <i>refinement</i> relationship
-between <a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">
-RandomAccessIterator</a> and the concepts which it builds upon:
-<a href="http://www.sgi.com/tech/stl/BidirectionalIterator.html">
-BidirectionalIterator</a> and
-<a href="http://www.sgi.com/tech/stl/LessThanComparable.html">
-LessThanComparable</a>. We could have instead used
-<tt>BOOST_CLASS_REQUIRE</tt> and placed these requirements in the class
-body, however <tt>BOOST_CLASS_REQUIRE</tt> uses C++ language features that
-are less portable.
-
-<p>
-Next we check that the <tt>iterator_category</tt> of the iterator is
-either <tt>std::random_access_iterator_tag</tt> or a derived class.
-After that we write out some code that corresponds to the valid
-expressions of the <a
-href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">
-RandomAccessIterator</a> concept. Typedefs can also be added to
-enforce the associated types of the concept.
-
-<pre>
- template <class Iter>
- struct RandomAccessIteratorConcept
- {
- void constraints() {
- function_requires< BidirectionalIteratorConcept<Iter> >();
- function_requires< LessThanComparableConcept<Iter> >();
- function_requires< ConvertibleConcept<
- typename std::iterator_traits<Iter>::iterator_category,
- std::random_access_iterator_tag> >();
-
- i += n;
- i = i + n; i = n + i;
- i -= n;
- i = i - n;
- n = i - j;
- i[n];
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+ "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+
+<html xmlns="http://www.w3.org/1999/xhtml">
+<!-- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000 -->
+<!-- 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) -->
+
+<head>
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+ <meta name="generator" content=
+ "HTML Tidy for Linux/x86 (vers 1 September 2005), see www.w3.org" />
+
+ <title>Creating Concept Checking Classes</title>
+ <link rel="stylesheet" href="../../rst.css" type="text/css" />
+</head>
+
+<body bgcolor="#FFFFFF" link="#0000EE" text="#000000" vlink="#551A8B" alink=
+"#FF0000">
+ <img src="../../boost.png" alt="C++ Boost" width="277" height=
+ "86" /><br clear="none" />
+
+ <h2><a name="creating-concept-checks" id="creating-concept-checks">Creating
+ Concept Checking Classes</a></h2>
+
+ <p>As an example of how to create a concept checking class template, we
+ look at how to create the corresponding checks for the <a href=
+ "http://www.sgi.com/tech/stl/InputIterator.html">InputIterator</a> concept.
+ The complete definition is here:</p>
+ <pre>
+template <class X>
+struct InputIterator
+ : Assignable<X>, EqualityComparable<X>
+{
+ private:
+ typedef std::iterator_traits<X> t;
+ public:
+ typedef typename t::value_type value_type;
+ typedef typename t::difference_type difference_type;
+ typedef typename t::reference reference;
+ typedef typename t::pointer pointer;
+ typedef typename t::iterator_category iterator_category;
+
+ BOOST_CONCEPT_ASSERT((SignedInteger<difference_type>));
+ BOOST_CONCEPT_ASSERT((Convertible<iterator_category, std::input_iterator_tag>));
+
+ BOOST_CONCEPT_USAGE(InputIterator)
+ {
+ X j(i); <font color=
+"green">// require copy construction</font>
+ same_type(*i++,v); <font color=
+"green">// require postincrement-dereference returning value_type</font>
+ X& x = ++j; <font color=
+"green">// require preincrement returning X&</font>
}
- Iter i, j;
- typename std::iterator_traits<Iter>::difference_type n;
- };
-}
+
+ private:
+ X i;
+ value_type v;
+
+ <font color=
+"green">// Type deduction will fail unless the arguments have the same type.</font>
+ template <typename T>
+ void same_type(T const&, T const&);
+};
</pre>
-One potential pitfall in designing concept checking classes is using
-more expressions in the constraint function than necessary. For
-example, it is easy to accidentally use the default constructor to
-create the objects that will be needed in the expressions (and not all
-concepts require a default constructor). This is the reason we write
-the constraint function as a member function of a class. The objects
-involved in the expressions are declared as data members of the class.
-Since objects of the constraints class template are never
-instantiated, the default constructor for the concept checking class
-is never instantiated. Hence the data member's default constructors
-are never instantiated (C++ Standard Section 14.7.1 9).
-
-<p>
-Next: Concept Covering and Archetypes<br>
-Prev: Using Concept Checks
-
-
-<br>
-<HR>
-<TABLE>
-<TR valign=top>
-<TD nowrap>Copyright © 2000</TD><TD>
-Jeremy Siek(<A
-HREF="mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</A>)
-Andrew Lumsdaine</A>(<A HREF="mailto:lums_at_[hidden]">lums_at_[hidden]</A>)
-</TD></TR></TABLE>
+ <h3>Walkthrough</h3>
+
+ <p>First, as a convention we name the concept checking class after the
+ concept. Next, since InputIterator is a refinement of Assignable and
+ EqualityComparable, we derive its concept checking class from the checking
+ classes for those other concepts. The library will automatically check for
+ conformance to Assignable and EqualityComparable whenever it checks the
+ InputIterator concept.</p>
+
+ <p>Next, we declare the concept's <a href=
+ "../../more/generic_programming.html#associated_type">associated types</a>
+ as member typedefs. The associated difference type is required to be a
+ signed integer, and the iterator category has to be convertible to
+ std::input_iterator_tag, so we assert those relationships. The syntax for
+ accessing associated types through the concept-checking template mirrors
+ the <a href=
+ "http://www.generic-programming.org/languages/conceptcpp/">proposed</a>
+ syntax for associated type access in C++0x Finally, we use the
+ <code>BOOST_CONCEPT_USAGE</code> macro to declare the function that
+ exercises all the concept's valid expressions. Note that at this point you
+ may sometimes need to be a little creative: for example, to check that
+ <code>*i++</code> returns the iterator's value type, we pass both values to
+ the <code>same_type</code> member function template, which requires both
+ arguments to have the same type, modulo references and cv-qualification.
+ It's an imperfect check, but it's better than nothing.</p>
+
+ <h3>Values for Usage Patterns Should Be Data Members</h3>
+
+ <p>You may be wondering why we declared <code>i</code> and <code>v</code>
+ as data members in the example above. Why didn't we simply write the
+ following?</p>
+ <pre>
+BOOST_CONCEPT_USAGE(InputIterator)
+{
+ X i; <font color=
+"green">// create the values we need</font>
+ value_type v;
+
+ X j(i); <font color=
+"green">// require copy construction</font>
+ same_type(*i++,v); <font color=
+"green">// require postincrement-dereference returning value_type</font>
+ X& x = ++j; <font color=
+"green">// require preincrement returning X&</font>
+}
+</pre>
-</BODY>
-</HTML>
+ <p>Unfortunately, that code wouldn't have worked out so well, because it
+ unintentionally imposes the requirement that <code>X</code> and its value
+ type are both default-constructible. On the other hand, since instances of
+ the <code>InputIterator</code> template will never be constructed, the
+ compiler never has to check how its data members will be constructed (C++
+ Standard Section 14.7.1 9). For that reason you should <strong>always
+ declare values needed for usage patterns as data members</strong>.</p>
+
+ <p>These sorts of errors in concept definitions can be detected by the use
+ of Concept Archetypes, but it's always
+ better to avoid them pre-emptively.</p>
+
+ <h3>Similarity to Proposed C++0x Language Support for Concepts</h3>
+
+ <p>This library's syntaxes for concept refinement and for access of
+ associated types mirrors the corresponding <a href=
+ "http://www.generic-programming.org/languages/conceptcpp/">proposed</a>
+ syntaxes in C++0x. However, C++0x will use
+ âsignaturesâ rather than usage patterns to
+ describe the valid operations on types participating in a concept, so when
+ converting your concept checking classes into language-supported concepts,
+ you'll need to translate your usage function into a series of
+ signatures.</p>
+
+ <p><a href="./concept_covering.htm">Next: Concept Covering and
+ Archetypes</a><br />
+ <a href="./using_concept_check.htm">Prev: Using Concept
+ Checks</a><br /></p>
+ <hr />
+
+ <table>
+ <tr valign="top">
+ <td nowrap="nowrap">Copyright © 2000</td>
+
+ <td>Jeremy Siek(<a href=
+ "mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</a>) Andrew
+ Lumsdaine(<a href="mailto:lums_at_[hidden]">lums_at_[hidden]</a>),
+ 2007 <a href="mailto:dave_at_[hidden]">David Abrahams</a>.
+ </tr>
+ </table>
+</body>
+</html>
Modified: trunk/libs/concept_check/fake_sort.hpp
==============================================================================
--- trunk/libs/concept_check/fake_sort.hpp (original)
+++ trunk/libs/concept_check/fake_sort.hpp 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -13,7 +13,7 @@
using namespace boost;
template<typename RanIter>
- BOOST_CONCEPT_WHERE(
+ BOOST_CONCEPT_REQUIRES(
((Mutable_RandomAccessIterator<RanIter>))
((LessThanComparable<typename Mutable_RandomAccessIterator<RanIter>::value_type>))
Modified: trunk/libs/concept_check/implementation.htm
==============================================================================
--- trunk/libs/concept_check/implementation.htm (original)
+++ trunk/libs/concept_check/implementation.htm 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -1,50 +1,59 @@
-<HTML>
-<!--
- -- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000
- --
- -- Permission to use, copy, modify, distribute and sell this software
- -- and its documentation for any purpose is hereby granted without fee,
- -- provided that the above copyright notice appears in all copies and
- -- that both that copyright notice and this permission notice appear
- -- in supporting documentation. We make no
- -- representations about the suitability of this software for any
- -- purpose. It is provided "as is" without express or implied warranty.
- -->
-<Head>
-<Title>Concept Checking Implementation</Title>
-<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
- ALINK="#ff0000">
-<IMG SRC="../../boost.png"
- ALT="C++ Boost" width="277" height="86">
-
-<BR Clear>
-
-
-<h2><a name="implementation">Implementation</a></h2>
-
-Ideally we would like to catch, and indicate, the concept violation at
-the point of instantiation. As mentioned in D&E[<a
-href="bibliography.htm#stroustrup94:_design_evolution">2</a>], the error
-can be caught by exercising all of the requirements needed by the
-function template. Exactly how the requirements (the valid
-expressions in particular) are exercised is a tricky issue, since we
-want the code to be compiled --- <i>but not executed</i>. Our
-approach is to exercise the requirements in a separate function that
-is assigned to a function pointer. In this case, the compiler will
-instantiate the function but will not actually invoke it. In
-addition, an optimizing compiler will remove the pointer assignment as
-``dead code'' (though the run-time overhead added by the assignment
-would be trivial in any case). It might be conceivable for a compiler
-to skip the semantic analysis and compilation of the constraints
-function in the first place, which would make our function pointer
-technique ineffective. However, this is unlikely because removal of
-unnecessary code and functions is typically done in later stages of a
-compiler. We have successfully used the function pointer technique
-with GNU C++, Microsoft Visual C++, and several EDG-based compilers
-(KAI C++, SGI MIPSpro). The following code shows how this technique
-can be applied to the <tt>std::stable_sort()</tt> function:
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+ "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-<pre>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<!-- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000, David Abrahams 2007 -->
+<!-- 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) -->
+
+<head>
+ <meta name="generator" content=
+ "HTML Tidy for Linux/x86 (vers 1 September 2005), see www.w3.org" />
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+ <link rel="stylesheet" href="../../rst.css" type="text/css" />
+
+ <title>Concept Checking Implementation</title>
+</head>
+
+<body bgcolor="#FFFFFF" link="#0000EE" text="#000000" vlink="#551A8B" alink=
+"#FF0000">
+ <img src="../../boost.png" alt="C++ Boost" width="277" height=
+ "86" /><br clear="none" />
+
+ <h2><a name="warning" id="warning"><font color=
+ "red">Warning</font></a></h2>
+
+ <p><font color="red">This documentation is out-of-date; similar but
+ newer implementation techniques are now used. This documentation
+ also refers to components and protocols in the library's old
+ interace such as <code>BOOST_CLASS_REQUIRES</code>
+ and <code>constraints()</code> functions, which are still supported
+ but deprecated.</font></p>
+
+ <h2><a name="implementation" id="implementation">Implementation</a></h2>
+
+ <p>Ideally we would like to catch, and indicate, the concept violation at
+ the point of instantiation. As mentioned in D&E[<a href=
+ "bibliography.htm#stroustrup94:_design_evolution">2</a>], the error can be
+ caught by exercising all of the requirements needed by the function
+ template. Exactly how the requirements (the valid expressions in
+ particular) are exercised is a tricky issue, since we want the code to be
+ compiledâ<i>but not executed</i>. Our approach is to exercise the
+ requirements in a separate function that is assigned to a function pointer.
+ In this case, the compiler will instantiate the function but will not
+ actually invoke it. In addition, an optimizing compiler will remove the
+ pointer assignment as ``dead code'' (though the run-time overhead added by
+ the assignment would be trivial in any case). It might be conceivable for a
+ compiler to skip the semantic analysis and compilation of the constraints
+ function in the first place, which would make our function pointer
+ technique ineffective. However, this is unlikely because removal of
+ unnecessary code and functions is typically done in later stages of a
+ compiler. We have successfully used the function pointer technique with GNU
+ C++, Microsoft Visual C++, and several EDG-based compilers (KAI C++, SGI
+ MIPSpro). The following code shows how this technique can be applied to the
+ <tt>std::stable_sort()</tt> function:</p>
+ <pre>
template <class RandomAccessIterator>
void stable_sort_constraints(RandomAccessIterator i)
{
@@ -57,24 +66,23 @@
void stable_sort(RandomAccessIterator first, RandomAccessIterator last)
{
typedef void (*fptr_type)(RandomAccessIterator);
- fptr_type x = &stable_sort_constraints;
+ fptr_type x = &stable_sort_constraints;
...
}
</pre>
-There is often a large set of requirements that need to be checked,
-and it would be cumbersome for the library implementor to write
-constraint functions like <tt>stable_sort_constraints()</tt> for every
-public function. Instead, we group sets of valid expressions
-together, according to the definitions of the corresponding concepts.
-For each concept we define a concept checking class template where the
-template parameter is for the type to be checked. The class contains
-a <tt>contraints()</tt> member function which exercises all of the
-valid expressions of the concept. The objects used in the constraints
-function, such as <tt>n</tt> and <tt>i</tt>, are declared as data
-members of the concept checking class.
-
-<pre>
+ <p>There is often a large set of requirements that need to be checked, and
+ it would be cumbersome for the library implementor to write constraint
+ functions like <tt>stable_sort_constraints()</tt> for every public
+ function. Instead, we group sets of valid expressions together, according
+ to the definitions of the corresponding concepts. For each concept we
+ define a concept checking class template where the template parameter is
+ for the type to be checked. The class contains a <tt>contraints()</tt>
+ member function which exercises all of the valid expressions of the
+ concept. The objects used in the constraints function, such as <tt>n</tt>
+ and <tt>i</tt>, are declared as data members of the concept checking
+ class.</p>
+ <pre>
template <class Iter>
struct RandomAccessIteratorConcept
{
@@ -90,18 +98,14 @@
};
</pre>
-We can still use the function pointer mechanism to cause instantiation
-of the constraints function, however now it will be a member function
-pointer. To make it easy for the library implementor to invoke the
-concept checks, we wrap the member function pointer mechanism in a
-function named <tt>function_requires()</tt>. The following code
-snippet shows how to use <tt>function_requires()</tt> to make sure
-that the iterator is a
-<a
-href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">
-RandomAccessIterator</a>.
-
-<pre>
+ <p>We can still use the function pointer mechanism to cause instantiation
+ of the constraints function, however now it will be a member function
+ pointer. To make it easy for the library implementor to invoke the concept
+ checks, we wrap the member function pointer mechanism in a function named
+ <tt>function_requires()</tt>. The following code snippet shows how to use
+ <tt>function_requires()</tt> to make sure that the iterator is a <a href=
+ "http://www.sgi.com/tech/stl/RandomAccessIterator.html">RandomAccessIterator</a>.</p>
+ <pre>
template <class Iter>
void stable_sort(Iter first, Iter last)
{
@@ -110,16 +114,15 @@
}
</pre>
-The definition of the <tt>function_requires()</tt> is as follows. The
-<tt>Concept</tt> is the concept checking class that has been
-instantiated with the modeling type. We assign the address of the
-constraints member function to the function pointer <tt>x</tt>, which
-causes the instantiation of the constraints function and checking of
-the concept's valid expressions. We then assign <tt>x</tt> to
-<tt>x</tt> to avoid unused variable compiler warnings, and wrap
-everything in a do-while loop to prevent name collisions.
-
-<pre>
+ <p>The definition of the <tt>function_requires()</tt> is as follows. The
+ <tt>Concept</tt> is the concept checking class that has been instantiated
+ with the modeling type. We assign the address of the constraints member
+ function to the function pointer <tt>x</tt>, which causes the instantiation
+ of the constraints function and checking of the concept's valid
+ expressions. We then assign <tt>x</tt> to <tt>x</tt> to avoid unused
+ variable compiler warnings, and wrap everything in a do-while loop to
+ prevent name collisions.</p>
+ <pre>
template <class Concept>
void function_requires()
{
@@ -128,17 +131,16 @@
}
</pre>
-To check the type parameters of class templates, we provide the
-<tt>BOOST_CLASS_REQUIRE</tt> macro which can be used inside the body of a
-class definition (whereas <tt>function_requires()</tt> can only be used
-inside of a function body). This macro declares a nested class
-template, where the template parameter is a function pointer. We then
-use the nested class type in a typedef with the function pointer type
-of the constraint function as the template argument. We use the
-<tt>type_var</tt> and <tt>concept</tt> names in the nested class and
-typedef names to help prevent name collisions.
-
-<pre>
+ <p>To check the type parameters of class templates, we provide the
+ <tt>BOOST_CLASS_REQUIRE</tt> macro which can be used inside the body of a
+ class definition (whereas <tt>function_requires()</tt> can only be used
+ inside of a function body). This macro declares a nested class template,
+ where the template parameter is a function pointer. We then use the nested
+ class type in a typedef with the function pointer type of the constraint
+ function as the template argument. We use the <tt>type_var</tt> and
+ <tt>concept</tt> names in the nested class and typedef names to help
+ prevent name collisions.</p>
+ <pre>
#define BOOST_CLASS_REQUIRE(type_var, ns, concept) \
typedef void (ns::concept <type_var>::* func##type_var##concept)(); \
template <func##type_var##concept _Tp1> \
@@ -148,14 +150,12 @@
concept_checking_typedef_##type_var##concept
</pre>
-In addition, there are versions of <tt>BOOST_CLASS_REQUIRE</tt> that
-take more arguments, to handle concepts that include interactions
-between two or more types. <tt>BOOST_CLASS_REQUIRE</tt> was not used
-in the implementation of the BCCL concept checks because some
-compilers do not implement template parameters of function pointer
-type.
-
-<!-- We decided not to go with this version since it is easier to misuse
+ <p>In addition, there are versions of <tt>BOOST_CLASS_REQUIRE</tt> that
+ take more arguments, to handle concepts that include interactions between
+ two or more types. <tt>BOOST_CLASS_REQUIRE</tt> was not used in the
+ implementation of the BCCL concept checks because some compilers do not
+ implement template parameters of function pointer type.
+ <!-- We decided not to go with this version since it is easier to misuse
To check the type parameters of class templates, we provide the
<tt>class_requires</tt> class which can be used inside the body of a
@@ -184,21 +184,22 @@
compilers do not implement template parameters of function pointer
type.
--->
-
-<p>
-Next: Reference<br>
-Prev: Programming With Concepts
-
-<br>
-<HR>
-<TABLE>
-<TR valign=top>
-<TD nowrap>Copyright © 2000</TD><TD>
-Jeremy Siek(<A
-HREF="mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</A>)
-Andrew Lumsdaine</A>(<A HREF="mailto:lums_at_[hidden]">lums_at_[hidden]</A>)
-</TD></TR></TABLE>
+--></p>
-</BODY>
-</HTML>
+ <p>Next: Reference<br />
+ <a href="prog_with_concepts.htm">Prev: Programming With
+ Concepts</a><br /></p>
+ <hr />
+
+ <table>
+ <tr valign="top">
+ <td nowrap="nowrap">Copyright © 2000</td>
+
+ <td>Jeremy Siek(<a href=
+ "mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</a>) Andrew
+ Lumsdaine(<a href="mailto:lums_at_[hidden]">lums_at_[hidden]</a>),
+ 2007 <a href="mailto:dave_at_[hidden]">David Abrahams</a>.
+ </tr>
+ </table>
+</body>
+</html>
Modified: trunk/libs/concept_check/prog_with_concepts.htm
==============================================================================
--- trunk/libs/concept_check/prog_with_concepts.htm (original)
+++ trunk/libs/concept_check/prog_with_concepts.htm 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -1,57 +1,55 @@
-<HTML>
-<!--
- -- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000
- --
- -- Permission to use, copy, modify, distribute and sell this software
- -- and its documentation for any purpose is hereby granted without fee,
- -- provided that the above copyright notice appears in all copies and
- -- that both that copyright notice and this permission notice appear
- -- in supporting documentation. We make no
- -- representations about the suitability of this software for any
- -- purpose. It is provided "as is" without express or implied warranty.
- -->
-<Head>
-<Title>Programming With Concepts</Title>
-<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
- ALINK="#ff0000">
-<IMG SRC="../../boost.png"
- ALT="C++ Boost" width="277" height="86">
-
-<BR Clear>
-
-<h2><a name="programming-with-concepts">Programming with Concepts</a></h2>
-
-The process of deciding how to group requirements into concepts and
-deciding which concepts to use in each algorithm is perhaps the most
-difficult (yet most important) part of building a generic library.
-A guiding principle to use during this process is one we
-call the <i>requirement minimization principle</i>.
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+ "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-<p>
-<b>Requirement Minimization Principle:</b> Minimize the requirements
-on the input parameters of a component to increase its reusability.
-
-<p>
-There is natural tension in this statement. By definition, the input
-parameters must be used by the component in order for the component to
-accomplish its task (by ``component'' we mean a function or class
-template). The challenge then is to implement the component in such a
-way that makes the fewest assumptions (the minimum requirements) about
-the inputs while still accomplishing the task.
-
-<p>
-The traditional notions of <i>abstraction</i> tie in directly to the
-idea of minimal requirements. The more abstract the input, the fewer
-the requirements. Thus, concepts are simply the embodiment of generic
-abstract data types in C++ template programming.
-
-<p>
-When designing the concepts for some problem domain it is important to
-keep in mind their purpose, namely to express the requirements for the
-input to the components. With respect to the requirement minimization
-principle, this means we want to minimize concepts.
-
-<!-- the following discussion does not match the Standard definition
+<html xmlns="http://www.w3.org/1999/xhtml">
+<!-- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000 -->
+<!-- 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) -->
+
+<head>
+ <meta name="generator" content=
+ "HTML Tidy for Linux/x86 (vers 1 September 2005), see www.w3.org" />
+
+ <title>Programming With Concepts</title>
+ <meta http-equiv="Content-Type" content="text/html; charset=us-ascii" />
+ <link rel="stylesheet" href="../../rst.css" type="text/css" />
+</head>
+
+<body bgcolor="#FFFFFF" link="#0000EE" text="#000000" vlink="#551A8B" alink=
+"#FF0000">
+ <img src="../../boost.png" alt="C++ Boost" width="277" height=
+ "86" /><br clear="none" />
+
+ <h2><a name="programming-with-concepts" id=
+ "programming-with-concepts">Programming with Concepts</a></h2>
+
+ <p>The process of deciding how to group requirements into concepts and
+ deciding which concepts to use in each algorithm is perhaps the most
+ difficult (yet most important) part of building a generic library. A
+ guiding principle to use during this process is one we call the
+ <i>requirement minimization principle</i>.</p>
+
+ <p><b>Requirement Minimization Principle:</b> Minimize the requirements on
+ the input parameters of a component to increase its reusability.</p>
+
+ <p>There is natural tension in this statement. By definition, the input
+ parameters must be used by the component in order for the component to
+ accomplish its task (by ``component'' we mean a function or class
+ template). The challenge then is to implement the component in such a way
+ that makes the fewest assumptions (the minimum requirements) about the
+ inputs while still accomplishing the task.</p>
+
+ <p>The traditional notions of <i>abstraction</i> tie in directly to the
+ idea of minimal requirements. The more abstract the input, the fewer the
+ requirements. Thus, concepts are simply the embodiment of generic abstract
+ data types in C++ template programming.</p>
+
+ <p>When designing the concepts for some problem domain it is important to
+ keep in mind their purpose, namely to express the requirements for the
+ input to the components. With respect to the requirement minimization
+ principle, this means we want to minimize concepts.
+ <!-- the following discussion does not match the Standard definition
of LessThanComparable and needs to be changed -Jeremy
<p>
@@ -88,7 +86,7 @@
<tt>></tt>, <tt><=</tt>, <tt>>=</tt>) are conceptually equivalent (in
a mathematical sense). Adding conceptually equivalent valid
expressions is not a violation of the requirement minimization
-principle because no new semantics are being added --- only new
+principle because no new semantics are being added === only new
syntax. The added syntax increases re-usability.
<p>
@@ -105,44 +103,42 @@
<tt>std::stable_sort()</tt>, then the maintainer is given a reasonable
amount of flexibility within which to work.
--->
-
-<p>
-Minimality in concepts is a property associated with the underlying
-semantics of the problem domain being represented. In the problem
-domain of basic containers, requiring traversal in a single direction
-is a smaller requirement than requiring traversal in both directions
-(hence the distinction between <a
-href="http://www.sgi.com/tech/stl/ForwardIterator.html">
-ForwardIterator</a> and
-<a
-href="http://www.sgi.com/tech/stl/BidirectionalIterator.html">
-BidirectionalIterator</a>). The semantic difference can be easily seen
-in the difference between the set of concrete data structures that
-have forward iterators versus the set that has bidirectional
-iterators. For example, singly-linked lists would fall in the set of
-data structures having forward iterators, but not bidirectional
-iterators. In addition, the set of algorithms that one can implement
-using only forward iterators is quite different than the set that can
-be implemented with bidirectional iterators. Because of this, it is
-important to factor families of requirements into rather fine-grained
-concepts. For example, the requirements for iterators are factored
-into the six STL iterator concepts (trivial, output, input, forward,
-bidirectional, and random access).
-
-<p>
-Next: Implementation<br>
-Prev: Concept Covering and Archetypes
-
-<br>
-<HR>
-<TABLE>
-<TR valign=top>
-<TD nowrap>Copyright © 2000</TD><TD>
-Jeremy Siek(<A
-HREF="mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</A>)
-Andrew Lumsdaine</A>(<A HREF="mailto:lums_at_[hidden]">lums_at_[hidden]</A>)
-</TD></TR></TABLE>
+--></p>
-</BODY>
-</HTML>
+ <p>Minimality in concepts is a property associated with the underlying
+ semantics of the problem domain being represented. In the problem domain of
+ basic containers, requiring traversal in a single direction is a smaller
+ requirement than requiring traversal in both directions (hence the
+ distinction between <a href=
+ "http://www.sgi.com/tech/stl/ForwardIterator.html">ForwardIterator</a> and
+ <a href=
+ "http://www.sgi.com/tech/stl/BidirectionalIterator.html">BidirectionalIterator</a>).
+ The semantic difference can be easily seen in the difference between the
+ set of concrete data structures that have forward iterators versus the set
+ that has bidirectional iterators. For example, singly-linked lists would
+ fall in the set of data structures having forward iterators, but not
+ bidirectional iterators. In addition, the set of algorithms that one can
+ implement using only forward iterators is quite different than the set that
+ can be implemented with bidirectional iterators. Because of this, it is
+ important to factor families of requirements into rather fine-grained
+ concepts. For example, the requirements for iterators are factored into the
+ six STL iterator concepts (trivial, output, input, forward, bidirectional,
+ and random access).</p>
+
+ <p>Next: Implementation<br />
+ <a href="./concept_covering.htm">Prev: Concept Covering and
+ Archetypes</a><br /></p>
+ <hr />
+
+ <table>
+ <tr valign="top">
+ <td nowrap="nowrap">Copyright © 2000</td>
+
+ <td>Jeremy Siek(<a href=
+ "mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</a>) Andrew
+ Lumsdaine(<a href="mailto:lums_at_[hidden]">lums_at_[hidden]</a>),
+ 2007 <a href="mailto:dave_at_[hidden]">David Abrahams</a>.
+ </tr>
+ </table>
+</body>
+</html>
Modified: trunk/libs/concept_check/reference.htm
==============================================================================
--- trunk/libs/concept_check/reference.htm (original)
+++ trunk/libs/concept_check/reference.htm 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -1,308 +1,391 @@
-<HTML>
-<!--
- -- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000
- --
- -- Permission to use, copy, modify, distribute and sell this software
- -- and its documentation for any purpose is hereby granted without fee,
- -- provided that the above copyright notice appears in all copies and
- -- that both that copyright notice and this permission notice appear
- -- in supporting documentation. We make no
- -- representations about the suitability of this software for any
- -- purpose. It is provided "as is" without express or implied warranty.
- -->
-<Head>
-<Title>Boost Concept Checking Reference</Title>
-</Head>
-<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
- ALINK="#ff0000">
-<IMG SRC="../../boost.png"
- ALT="C++ Boost" width="277" height="86">
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+ "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-<BR Clear>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<!-- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000 -->
+<!-- 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) -->
-<h2><a name="reference">Reference</a></h2>
+<head>
+ <meta name="generator" content=
+ "HTML Tidy for Linux/x86 (vers 1 September 2005), see www.w3.org" />
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+ <link rel="stylesheet" href="../../rst.css" type="text/css" />
- <OL>
- <LI>Functions</LI>
- <LI>Macros</LI>
- <LI>Basic Concept Checking Classes</LI>
- <LI>Iterator Concept Checking Classes</LI>
- <LI>Function Object Concept Checking Classes</LI>
- <LI>Container Concept Checking Classes</LI>
- <LI>Basic Archetype Classes</LI>
- <LI>Iterator Archetype Classes</LI>
- <LI>Function Object Archetype Classes</LI>
- <LI>Container Archetype Classes</LI>
- </OL>
+ <title>Boost Concept Checking Reference</title>
+</head>
-<h3><a name="functions">Functions</a></h3>
+<body bgcolor="#FFFFFF" link="#0000EE" text="#000000" vlink="#551A8B" alink=
+"#FF0000">
+ <img src="../../boost.png" alt="C++ Boost" width="277" height=
+ "86" /><br clear="none" />
-<pre>
- template <class Concept>
- void function_requires();
-</pre>
+ <h2><a name="reference" id="reference">Reference</a></h2>
-<h3><a name="macros">Macros</a></h3>
+ <ol>
+ <li>Macros</li>
-<pre>
- // Apply concept checks in class definitions.
- BOOST_CLASS_REQUIRE(<i>type</i>, <i>namespace-of-concept</i>, <i>concept</i>);
- BOOST_CLASS_REQUIRE2(<i>type1</i>, <i>type2</i>, <i>namespace-of-concept</i>, <i>concept</i>);
- BOOST_CLASS_REQUIRE3(<i>type1</i>, <i>type2</i>, <i>type3</i>, <i>namespace-of-concept</i>, <i>concept</i>);
- BOOST_CLASS_REQUIRE4(<i>type1</i>, <i>type2</i>, <i>type3</i>, <i>type4</i>, <i>namespace-of-concept</i>, <i>concept</i>);
-</pre>
+ <li>Basic Concept Checking Classes</li>
+
+ <li><a href="#iterator-concepts">Iterator Concept Checking
+ Classes</a></li>
+
+ <li><a href="#function-object-concepts">Function Object Concept Checking
+ Classes</a></li>
+
+ <li><a href="#container-concepts">Container Concept Checking
+ Classes</a></li>
+
+ <li>Basic Archetype Classes</li>
+
+ <li>Iterator Archetype Classes</li>
+
+ <li><a href="#function-object-archetype">Function Object Archetype
+ Classes</a></li>
+
+ <li>Container Archetype Classes</li>
-Deprecated macros:
+ <li>Deprecated Functions</li>
-<pre>
- // Apply concept checks in class definitions.
- BOOST_CLASS_REQUIRES(<i>type</i>, <i>concept</i>);
- BOOST_CLASS_REQUIRES2(<i>type1</i>, <i>type2</i>, <i>concept</i>);
- BOOST_CLASS_REQUIRES3(<i>type1</i>, <i>type2</i>, <i>type3</i>, <i>concept</i>);
- BOOST_CLASS_REQUIRES4(<i>type1</i>, <i>type2</i>, <i>type3</i>, <i>type4</i>, <i>concept</i>);
+ <li>Deprecated Macros</li>
+
+ <li><a href="#deprecated-concept-checking-classes">Deprecated Concept
+ Checking Classes</a></li>
+ </ol>
+
+ <h3><a name="macros" id="macros">Macros</a></h3>
+ <pre>
+#include "boost/concept/assert.hpp"
+
+BOOST_CONCEPT_ASSERT((<em>concept checking class template specialization</em>));
</pre>
-<h3><a name="basic-concepts">Basic Concept Checking Classes</a></h3>
+ <p><strong>Effects:</strong> causes a compilation failure if the concept is
+ not satisfied.<br />
+ <strong>Note:</strong> this macro can be used at global, class, or function
+ scope.</p>
-<pre>
- template <class T>
- struct IntegerConcept; // Is T a built-in integer type?
+ <h3><a name="basic-concepts" id="basic-concepts">Basic Concept Checking
+ Classes</a></h3>
+ <pre>
+#include "boost/concept_check.hpp"
- template <class T>
- struct SignedIntegerConcept; // Is T a built-in signed integer type?
+template <class T>
+struct Integer; // Is T a built-in integer type?
- template <class T>
- struct UnsignedIntegerConcept; // Is T a built-in unsigned integer type?
+template <class T>
+struct SignedInteger; // Is T a built-in signed integer type?
- template <class X, class Y>
- struct ConvertibleConcept; // Is X convertible to Y?
+template <class T>
+struct UnsignedInteger; // Is T a built-in unsigned integer type?
- template <class T>
- struct AssignableConcept; // Standard ref 23.1
+template <class X, class Y>
+struct Convertible; // Is X convertible to Y?
- template <class T>
- struct SGIAssignableConcept;
+template <class T>
+struct <a href=
+"../utility/Assignable.html">Assignable</a>; // Standard ref 23.1
- template <class T>
- struct <a
- href="http://www.sgi.com/tech/stl/DefaultConstructible.html">DefaultConstructible</a>Concept;
+template <class T>
+struct SGI<a href=
+"http://www.sgi.com/tech/stl/Assignable.html">Assignable</a>;
- template <class T>
- struct CopyConstructibleConcept; // Standard ref 20.1.3
+template <class T>
+struct <a href=
+"http://www.sgi.com/tech/stl/DefaultConstructible.html">DefaultConstructible</a>;
- template <class T>
- struct EqualityComparableConcept; // Standard ref 20.1.1
+template <class T>
+struct <a href=
+"../utility/CopyConstructible.html">CopyConstructible</a>; // Standard ref 20.1.3
- template <class T>
- struct LessThanComparableConcept; // Standard ref 20.1.2
+template <class T>
+struct <a href=
+"http://www.sgi.com/tech/stl/EqualityComparable.html">EqualityComparable</a>; // Standard ref 20.1.1
- template <class T>
- struct ComparableConcept; // The SGI STL LessThanComparable concept
-</pre>
+template <class T>
+struct <a href=
+"../utility/LessThanComparable.html">LessThanComparable</a>; // Standard ref 20.1.2
-<h3><a name="iterator-concepts">Iterator Concept Checking Classes</a></h3>
+template <class T>
+struct Comparable; // The SGI STL <a href=
+"http://www.sgi.com/tech/stl/LessThanComparable.html">LessThanComparable</a> concept
+</pre>
-<pre>
- template <class Iter>
- struct InputIteratorConcept; // Standard ref 24.1.1 Table 72
+ <h3><a name="iterator-concepts" id="iterator-concepts">Iterator Concept
+ Checking Classes</a></h3>
+ <pre>
+template <class Iter>
+struct <a href=
+"http://www.sgi.com/tech/stl/InputIterator.html">InputIterator</a>; // Standard ref 24.1.1 Table 72
- template <class Iter, class T>
- struct OutputIteratorConcept; // Standard ref 24.1.2 Table 73
+template <class Iter, class T>
+struct <a href=
+"http://www.sgi.com/tech/stl/OutputIterator.html">OutputIterator</a>; // Standard ref 24.1.2 Table 73
- template <class Iter>
- struct ForwardIteratorConcept; // Standard ref 24.1.3 Table 74
+template <class Iter>
+struct <a href=
+"http://www.sgi.com/tech/stl/ForwardIterator.html">ForwardIterator</a>; // Standard ref 24.1.3 Table 74
- template <class Iter>
- struct Mutable_ForwardIteratorConcept;
+template <class Iter>
+struct Mutable_ForwardIterator;
- template <class Iter>
- struct BidirectionalIteratorConcept; // Standard ref 24.1.4 Table 75
+template <class Iter>
+struct <a href=
+"http://www.sgi.com/tech/stl/BidirectionalIterator.html">BidirectionalIterator</a>; // Standard ref 24.1.4 Table 75
- template <class Iter>
- struct Mutable_BidirectionalIteratorConcept;
+template <class Iter>
+struct Mutable_BidirectionalIterator;
- template <class Iter>
- struct RandomAccessIteratorConcept; // Standard ref 24.1.5 Table 76
+template <class Iter>
+struct <a href=
+"http://www.sgi.com/tech/stl/RandomAccessIterator.html">RandomAccessIterator</a>; // Standard ref 24.1.5 Table 76
- template <class Iter>
- struct Mutable_RandomAccessIteratorConcept;
+template <class Iter>
+struct Mutable_RandomAccessIterator;
</pre>
-<h3><a name="function-object-concepts">Function Object Concept Checking Classes</a></h3>
+ <h3><a name="function-object-concepts" id=
+ "function-object-concepts">Function Object Concept Checking
+ Classes</a></h3>
+ <pre>
+#include "boost/concept_check.hpp"
-<pre>
- template <class Func, class Return>
- struct GeneratorConcept;
+template <class Func, class Return>
+struct Generator;
- template <class Func, class Return, class Arg>
- struct UnaryFunctionConcept;
+template <class Func, class Return, class Arg>
+struct <a href=
+"http://www.sgi.com/tech/stl/UnaryFunction.html">UnaryFunction</a>;
- template <class Func, class Return, class First, class Second>
- struct BinaryFunctionConcept;
+template <class Func, class Return, class First, class Second>
+struct <a href=
+"http://www.sgi.com/tech/stl/BinaryFunction.html">BinaryFunction</a>;
- template <class Func, class Arg>
- struct UnaryPredicateConcept;
+template <class Func, class Arg>
+struct Unary<a href=
+"http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>;
- template <class Func, class First, class Second>
- struct BinaryPredicateConcept;
+template <class Func, class First, class Second>
+struct <a href=
+"http://www.sgi.com/tech/stl/BinaryPredicate.html">BinaryPredicate</a>;
- template <class Func, class First, class Second>
- struct Const_BinaryPredicateConcept;
+template <class Func, class First, class Second>
+struct Const_BinaryPredicate;
- template <class Func, class Return>
- struct AdaptableGeneratorConcept;
+template <class Func, class Return>
+struct <a href=
+"http://www.sgi.com/tech/stl/AdaptableGenerator.html">AdaptableGenerator</a>;
- template <class Func, class Return, class Arg>
- struct AdaptableUnaryFunctionConcept;
+template <class Func, class Return, class Arg>
+struct <a href=
+"http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>;
- template <class Func, class First, class Second>
- struct AdaptableBinaryFunctionConcept;
+template <class Func, class First, class Second>
+struct <a href=
+"http://www.sgi.com/tech/stl/AdaptableBinaryFunction.html">AdaptableBinaryFunction</a>;
- template <class Func, class Arg>
- struct AdaptablePredicateConcept;
+template <class Func, class Arg>
+struct <a href=
+"http://www.sgi.com/tech/stl/AdaptablePredicate.html">AdaptablePredicate</a>;
- template <class Func, class First, class Second>
- struct AdaptableBinaryPredicateConcept;
-
+template <class Func, class First, class Second>
+struct <a href=
+"http://www.sgi.com/tech/stl/AdaptableBinaryPredicate.html">AdaptableBinaryPredicate</a>;
</pre>
-<h3><a name="container-concepts">Container Concept Checking Classes</a></h3>
+ <h3><a name="container-concepts" id="container-concepts">Container Concept
+ Checking Classes</a></h3>
+ <pre>
+#include "boost/concept_check.hpp"
-<pre>
- template <class C>
- struct ContainerConcept; // Standard ref 23.1 Table 65
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/Container.html">Container</a>; // Standard ref 23.1 Table 65
- template <class C>
- struct Mutable_ContainerConcept;
+template <class C>
+struct Mutable_Container;
- template <class C>
- struct ForwardContainerConcept;
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/ForwardContainer.html">ForwardContainer</a>;
- template <class C>
- struct Mutable_ForwardContainerConcept;
+template <class C>
+struct Mutable_ForwardContainer;
- template <class C>
- struct ReversibleContainerConcept; // Standard ref 23.1 Table 66
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/ReversibleContainer.html">ReversibleContainer</a>; // Standard ref 23.1 Table 66
- template <class C>
- struct Mutable_ReversibleContainerConcept;
+template <class C>
+struct Mutable_ReversibleContainer;
- template <class C>
- struct RandomAccessContainerConcept;
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/RandomAccessContainer.html">RandomAccessContainer</a>;
- template <class C>
- struct Mutable_RandomAccessContainerConcept;
+template <class C>
+struct Mutable_RandomAccessContainer;
- template <class C>
- struct SequenceConcept; // Standard ref 23.1.1
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/Sequence.html">Sequence</a>; // Standard ref 23.1.1
- template <class C>
- struct FrontInsertionSequenceConcept;
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/FrontInsertionSequence.html">FrontInsertionSequence</a>;
- template <class C>
- struct BackInsertionSequenceConcept;
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/BackInsertionSequence.html">BackInsertionSequence</a>;
- template <class C>
- struct AssociativeContainerConcept; // Standard ref 23.1.2 Table 69
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/AssociativeContainer.html">AssociativeContainer</a>; // Standard ref 23.1.2 Table 69
- template <class C>
- struct UniqueAssociativeContainerConcept;
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/UniqueAssociativeContainer.html">UniqueAssociativeContainer</a>;
- template <class C>
- struct MultipleAssociativeContainerConcept;
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/MultipleAssociativeContainer.html">MultipleAssociativeContainer</a>;
- template <class C>
- struct SimpleAssociativeContainerConcept;
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/SimpleAssociativeContainer.html">SimpleAssociativeContainer</a>;
- template <class C>
- struct PairAssociativeContainerConcept;
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/PairAssociativeContainer.html">PairAssociativeContainer</a>;
- template <class C>
- struct SortedAssociativeContainerConcept;
+template <class C>
+struct <a href=
+"http://www.sgi.com/tech/stl/SortedAssociativeContainer.html">SortedAssociativeContainer</a>;
</pre>
+ <h3><a name="basic-archetype" id="basic-archetype">Basic Archetype
+ Classes</a></h3>
+ <pre>
+#include "boost/concept_archetype.hpp"
-<h3><a name="basic-archetype">Basic Archetype Classes</a></h3>
+template <class T = int>
+class null_archetype; // A type that models no concepts.
-<pre>
- template <class T = int>
- class null_archetype; // A type that models no concepts.
+template <class Base = null_archetype>
+class default_constructible_archetype;
- template <class Base = null_archetype>
- class default_constructible_archetype;
+template <class Base = null_archetype>
+class assignable_archetype;
- template <class Base = null_archetype>
- class assignable_archetype;
+template <class Base = null_archetype>
+class copy_constructible_archetype;
- template <class Base = null_archetype>
- class copy_constructible_archetype;
+template <class Base = null_archetype>
+class equality_comparable_archetype;
- template <class Base = null_archetype>
- class equality_comparable_archetype;
-
- template <class T, class Base = null_archetype>
- class convertible_to_archetype;
+template <class T, class Base = null_archetype>
+class convertible_to_archetype;
</pre>
-<h3><a name="iterator-archetype">Iterator Archetype Classes</a></h3>
-
-<pre>
- template <class ValueType>
- class trivial_iterator_archetype;
+ <h3><a name="iterator-archetype" id="iterator-archetype">Iterator Archetype
+ Classes</a></h3>
+ <pre>
+#include "boost/concept_archetype.hpp"
- template <class ValueType>
- class mutable_trivial_iterator_archetype;
+template <class ValueType>
+class trivial_iterator_archetype;
- template <class ValueType>
- class input_iterator_archetype;
+template <class ValueType>
+class mutable_trivial_iterator_archetype;
- template <class ValueType>
- class forward_iterator_archetype;
+template <class ValueType>
+class input_iterator_archetype;
- template <class ValueType>
- class bidirectional_iterator_archetype;
+template <class ValueType>
+class forward_iterator_archetype;
- template <class ValueType>
- class random_access_iterator_archetype;
+template <class ValueType>
+class bidirectional_iterator_archetype;
+template <class ValueType>
+class random_access_iterator_archetype;
</pre>
-<h3><a name="function-object-archetype">Function Object Archetype Classes</a></h3>
+ <h3><a name="function-object-archetype" id=
+ "function-object-archetype">Function Object Archetype Classes</a></h3>
+ <pre>
+#include "boost/concept_archetype.hpp"
-<pre>
- template <class Arg, class Return>
- class unary_function_archetype;
+template <class Arg, class Return>
+class unary_function_archetype;
- template <class Arg1, class Arg2, class Return>
- class binary_function_archetype;
+template <class Arg1, class Arg2, class Return>
+class binary_function_archetype;
- template <class Arg>
- class predicate_archetype;
+template <class Arg>
+class predicate_archetype;
- template <class Arg1, class Arg2>
- class binary_predicate_archetype;
+template <class Arg1, class Arg2>
+class binary_predicate_archetype;
</pre>
-<h3><a name="container-archetype">Container Archetype Classes</a></h3>
-
-<pre>
+ <h3><a name="container-archetype" id="container-archetype">Container
+ Archetype Classes</a></h3>
+ <pre>
UNDER CONSTRUCTION
</pre>
-<p>
-Back to Introduction
-<br>
-Prev: Implementation
-
-<br>
-<HR>
-<TABLE>
-<TR valign=top>
-<TD nowrap>Copyright © 2000</TD><TD>
-Jeremy Siek(<A
-HREF="mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</A>)
-Andrew Lumsdaine</A>(<A HREF="mailto:lums_at_[hidden]">lums_at_[hidden]</A>)
-</TD></TR></TABLE>
-
-</BODY>
-</HTML>
+ <h3><a name="deprecated-functions" id="deprecated-functions">Deprecated
+ Functions</a></h3>
+ <pre>
+#include "boost/concept_check.hpp"
+
+template <class Concept>
+void function_requires();
+</pre>
+
+ <h3><a name="deprecated-macros" id="deprecated-macros">Deprecated
+ Macros</a></h3>
+ <pre>
+#include "boost/concept_check.hpp"
+
+// Apply concept checks in class definitions.
+BOOST_CLASS_REQUIRE(<i>type</i>, <i>namespace-of-concept</i>, <i>concept</i>);
+BOOST_CLASS_REQUIRE2(<i>type1</i>, <i>type2</i>, <i>namespace-of-concept</i>, <i>concept</i>);
+BOOST_CLASS_REQUIRE3(<i>type1</i>, <i>type2</i>, <i>type3</i>, <i>namespace-of-concept</i>, <i>concept</i>);
+BOOST_CLASS_REQUIRE4(<i>type1</i>, <i>type2</i>, <i>type3</i>, <i>type4</i>, <i>namespace-of-concept</i>, <i>concept</i>);
+
+// Apply concept checks in class definitions.
+BOOST_CLASS_REQUIRES(<i>type</i>, <i>concept</i>);
+BOOST_CLASS_REQUIRES2(<i>type1</i>, <i>type2</i>, <i>concept</i>);
+BOOST_CLASS_REQUIRES3(<i>type1</i>, <i>type2</i>, <i>type3</i>, <i>concept</i>);
+BOOST_CLASS_REQUIRES4(<i>type1</i>, <i>type2</i>, <i>type3</i>, <i>type4</i>, <i>concept</i>);
+</pre>
+
+ <h3><a name="deprecated-concept-checking-classes" id=
+ "deprecated-concept-checking-classes">Deprecated Concept Checking
+ Classes</a></h3>
+
+ <p>For each of the concepts documented here, the library includes an
+ identical concept checking class whose name ends in
+ â<code>Concept</code>â For example, in
+ addition to <code>RandomAccessIterator</code>, the library defines a
+ <code>RandomAccessIteratorConcept</code> class template.</p>
+
+ <p>Back to Introduction<br />
+ Prev: Implementation<br /></p>
+ <hr />
+
+ <table>
+ <tr valign="top">
+ <td nowrap="nowrap">Copyright © 2000</td>
+
+ <td>Jeremy Siek(<a href=
+ "mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</a>) Andrew
+ Lumsdaine(<a href="mailto:lums_at_[hidden]">lums_at_[hidden]</a>), 2007
+ <a href="mailto:dave_at_[hidden]">David Abrahams</a>.</td>
+ </tr>
+ </table>
+</body>
+</html>
Modified: trunk/libs/concept_check/using_concept_check.htm
==============================================================================
--- trunk/libs/concept_check/using_concept_check.htm (original)
+++ trunk/libs/concept_check/using_concept_check.htm 2007-11-04 22:54:19 EST (Sun, 04 Nov 2007)
@@ -1,227 +1,186 @@
-<HTML>
-<!--
- -- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000
- --
- -- Permission to use, copy, modify, distribute and sell this software
- -- and its documentation for any purpose is hereby granted without fee,
- -- provided that the above copyright notice appears in all copies and
- -- that both that copyright notice and this permission notice appear
- -- in supporting documentation. We make no
- -- representations about the suitability of this software for any
- -- purpose. It is provided "as is" without express or implied warranty.
- -->
-<Head>
-<Title>Using Concept Checks</Title>
-<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
- ALINK="#ff0000">
-<IMG SRC="../../boost.png"
- ALT="C++ Boost" width="277" height="86">
-
-<BR Clear>
-
-
-<h2><a name="using-concept-checks">Using Concept Checks</a></h2>
-
-For each concept there is a concept checking class which can be used
-to make sure that a given type (or set of types) models the concept.
-The Boost Concept Checking Library (BCCL) includes concept checking classes
-for all of the concepts used in the C++ standard library and a few
-more. The Reference section lists these
-concept checking classes. In addition, other boost libraries come with
-concept checking classes for the concepts that are particular to those
-libraries. For example, there are <a
-href="../graph/doc/graph_concepts.html">graph concepts</a> and <a
-href="../property_map/property_map.html">property map concepts</a>.
-Also, whenever <b>anyone</b> writing a class of function template
-needs to express requirements that are not yet stated by an existing
-concept, a new concept checking class should be created. How
-to do this is explained in <a href="./creating_concepts.htm">Creating
-Concept Checking Classes</a>.
-
-<p>
-An example of a concept checking class from the BCCL is the
-<tt>EqualityComparableConcept</tt> class. The class corresponds to the
-EqualityComparable requirements described in 20.1.1 of the C++
-Standard, and to the <a
-href="http://www.sgi.com/tech/stl/EqualityComparable.html">EqualityComparable</a>
-concept documented in the SGI STL.
-
-<pre>
- template <class T>
- struct EqualityComparableConcept;
-</pre>
-
-The template argument <tt>T</tt> will the type to be checked. That is,
-the purpose of <tt>EqualityComparableConcept</tt> is to make sure that
-the template argument given for <tt>T</tt> models the
-EqualityComparable concept.
-
-<p>
-Each concept checking class has a member function named
-<tt>constraints()</tt> which contains the valid expressions for the
-concept. To check whether some type is EqualityComparable we need to
-instantiate the concept checking class with the type and then find a
-way to get the compiler to compile the <tt>constraints()</tt> function
-without actually executing the function. The Boost Concept Checking
-Library defines two utilities that make this easy:
-<tt>function_requires()</tt> and <tt>BOOST_CLASS_REQUIRE</tt>.
-
-<h4><tt>function_requires()</tt></h4>
-
-The <tt>function_requires()</tt> function can be used in function bodies
-and the <tt>BOOST_CLASS_REQUIRE</tt> macro can be used inside class
-bodies. The <tt>function_requires()</tt> function takes no arguments,
-but has a template parameter for the concept checking class. This
-means that the instantiated concept checking class must be given as an
-explicit template argument, as shown below.
-
-<pre>
- // In my library:
- template <class T>
- void generic_library_function(T x)
- {
- function_requires< EqualityComparableConcept<T> >();
- // ...
- };
-
- // In the user's code:
- class foo {
- //...
- };
-
- int main() {
- foo f;
- generic_library_function(f);
- return 0;
- }
-</pre>
-
-
-<h4><tt>BOOST_CLASS_REQUIRE</tt></h4>
-
-The <tt>BOOST_CLASS_REQUIRE</tt> macro can be used inside a class
-definition to check whether some type models a concept. Make sure
-that the arguments to this macro are simply identifiers. You may need
-to use typedef to get your types into this form.
-
-<pre>
- // In my library:
- template <class T>
- struct generic_library_class
- {
- BOOST_CLASS_REQUIRE(T, boost, EqualityComparableConcept);
- // ...
- };
-
- // In the user's code:
- class foo {
- //...
- };
-
- int main() {
- generic_library_class<foo> glc;
- // ...
- return 0;
- }
-</pre>
-
-
-<h4>Example</h4>
-
-<p>
-Getting back to the earlier <a
-href="./concept_check.htm#motivating-example">motivating example</a>,
-one good application of concept checks would be to insert
-<tt>function_requires()</tt> at the top of <tt>std::stable_sort()</tt>
-to make sure the template parameter type models <a
-href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">
-RandomAccessIterator</a>. In addition, <tt>std::stable_sort()</tt>
-requires that the <tt>value_type</tt> of the iterators be
-<a href="http://www.sgi.com/tech/stl/LessThanComparable.html">
-LessThanComparable</a>, so we also use <tt>function_requires()</tt> to
-check this.
-
-<pre>
- template <class RandomAccessIter>
- void stable_sort(RandomAccessIter first, RandomAccessIter last)
- {
- function_requires< RandomAccessIteratorConcept<RandomAccessIter> >();
- typedef typename std::iterator_traits<RandomAccessIter>::value_type value_type;
- function_requires< LessThanComparableConcept<value_type> >();
- ...
- }
-</pre>
-
-
-
-<!-- There are a few places where the SGI STL documentation differs
-from the corresponding requirements described in the C++ Standard. In
-these cases we use the definition from the C++ Standard. -->
-
-<p>
-Some concepts deal with more than one type. In this case the
-corresponding concept checking class will have multiple template
-parameters. The following example shows how
-<tt>function_requires()</tt> is used with the <a
-href="../property_map/ReadWritePropertyMap.html">ReadWritePropertyMap</a>
-concept which takes two type parameters: a property map and the key
-type for the map.
-
-<pre>
- template <class IncidenceGraph, class Buffer, class BFSVisitor,
- class ColorMap>
- void breadth_first_search(IncidenceGraph& g,
- typename graph_traits<IncidenceGraph>::vertex_descriptor s,
- Buffer& Q, BFSVisitor vis, ColorMap color)
- {
- typedef typename graph_traits<IncidenceGraph>::vertex_descriptor Vertex;
- function_requires< ReadWritePropertyMap<ColorMap, Vertex> >();
- ...
- }
-</pre>
-
-
-As an example of using <tt>BOOST_CLASS_REQUIRE</tt> we look at a concept
-check that could be added to <tt>std::vector</tt>. One requirement
-that is placed on the element type is that it must be <a
-href="http://www.sgi.com/tech/stl/Assignable.html">Assignable</a>.
-We can check this by inserting
-<tt>class_requires<AssignableConcept<T> ></tt> at the top
-of the definition for <tt>std::vector</tt>.
-
-<pre>
- namespace std {
- template <class T>
- struct vector {
- BOOST_CLASS_REQUIRE(T, boost, AssignableConcept);
- ...
- };
- }
-</pre>
-
-
-Although the concept checks are designed for use by generic library
-implementors, they can also be useful to end users. Sometimes one may
-not be sure whether some type models a particular concept. This can
-easily be checked by creating a small program and using
-<tt>function_requires()</tt> with the type and concept in question.
-The file <a
-href="./stl_concept_check.cpp"><tt>stl_concept_checks.cpp</tt></a>
-gives and example of applying the concept checks to STL containers.
-
-<p>
-Prev: Concept Checking Introduction <br>
-Next: Creating Concept Checking Classes
-
-<br>
-<HR>
-<TABLE>
-<TR valign=top>
-<TD nowrap>Copyright © 2000</TD><TD>
-Jeremy Siek(<A
-HREF="mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</A>)
-Andrew Lumsdaine</A>(<A HREF="mailto:lums_at_[hidden]">lums_at_[hidden]</A>)
-</TD></TR></TABLE>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+ "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-</BODY>
-</HTML>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<!-- Copyright (c) Jeremy Siek and Andrew Lumsdaine 2000 -->
+<!-- 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) -->
+
+<head>
+ <meta name="generator" content=
+ "HTML Tidy for Linux/x86 (vers 1 September 2005), see www.w3.org" />
+ <meta http-equiv="Content-Type" content="text/html; charset=us-ascii" />
+
+ <title>Using Concept Checks</title>
+ <link rel="stylesheet" href="../../rst.css" type="text/css" />
+</head>
+
+<body bgcolor="#FFFFFF" link="#0000EE" text="#000000" vlink="#551A8B" alink=
+"#FF0000">
+ <img src="../../boost.png" alt="C++ Boost" width="277" height=
+ "86" /><br clear="none" />
+
+ <h2><a name="using-concept-checks" id="using-concept-checks">Using Concept
+ Checks</a></h2>
+
+ <p>For each concept there is a concept checking class template that can be
+ used to make sure that a given type (or set of types) models the concept.
+ The Boost Concept Checking Library (BCCL) includes concept checking class
+ templates for all of the concepts used in the C++ standard library and a
+ few more. See the Reference section for a
+ complete list. In addition, other boost libraries come with concept
+ checking classes for the concepts that are particular to those libraries.
+ For example, there are <a href="../graph/doc/graph_concepts.html">graph
+ concepts</a> and <a href="../property_map/property_map.html">property map
+ concepts</a>. Also, whenever <b>anyone</b> writing function templates needs
+ to express requirements that are not yet stated by an existing concept, a
+ new concept checking class should be created. How to do this is explained
+ in <a href="./creating_concepts.htm">Creating Concept Checking
+ Classes</a>.</p>
+
+ <p>An example of a concept checking class from the BCCL is the
+ <tt>EqualityComparableConcept</tt> class. The class corresponds to the
+ EqualityComparable requirements described in 20.1.1 of the C++ Standard,
+ and to the <a href=
+ "http://www.sgi.com/tech/stl/EqualityComparable.html">EqualityComparable</a>
+ concept documented in the SGI STL.</p>
+ <pre>
+template <class T>
+struct EqualityComparable;
+</pre>
+
+ <p>The template argument is the type to be checked. That is, the purpose of
+ <tt>EqualityComparable<<em>X</em>></tt> is to make sure that
+ <tt><em>X</em></tt> models the EqualityComparable concept.</p>
+
+ <h4><tt>BOOST_CONCEPT_ASSERT()</tt></h4>
+
+ <p>The most versatile way of checking concept requirements is to use the
+ <code>BOOST_CONCEPT_ASSERT()</code> macro. You can use this macro at any
+ scope, by passing a concept checking template specialization enclosed in
+ parentheses. <strong>Note:</strong> that means invocations of
+ <code>BOOST_CONCEPT_ASSERT</code> will appear to use <strong>double
+ parentheses</strong>.</p>
+ <pre>
+<font color="green">// In my library:</font>
+template <class T>
+void generic_library_function(T x)
+{
+ BOOST_CONCEPT_ASSERT<strong>((</strong>EqualityComparable<T><strong>))</strong>;
+ <font color="green">// ...</font>
+};
+
+template <class It>
+class generic_library_class
+{
+ BOOST_CONCEPT_ASSERT<strong>((</strong>RandomAccessIterator<It><strong>))</strong>;
+ <font color="green">// ...</font>
+};
+
+<font color="green">// In the user's code:</font>
+class foo {
+ <font color="green">//... </font>
+};
+
+int main() {
+ foo x;
+ generic_library_function(x);
+ generic_library_class<std::vector<char>::iterator> y;
+ <font color="green">//...</font>
+}
+</pre>
+
+ <h4><tt>BOOST_CONCEPT_REQUIRES</tt></h4>
+
+ <p>One of the nice things about the proposed C++0x <a href=
+ "http://www.generic-programming.org/languages/conceptcpp/tutorial">syntax
+ for declaring concept constrained function templates</a> is the way that
+ constraints are part of the function <em>declaration</em>, so clients will
+ see them. <code>BOOST_CONCEPT_ASSERT</code> can only express constraints
+ within the function template definition, which hides the constraint in the
+ function body. Aside from the loss of a self-documenting interface,
+ asserting conformance only in the function body can undesirably delay
+ checking if the function is explicitly instantiated in a different
+ translation unit from the one in which it is called, or if the compiler
+ does link-time instantiation.</p>
+
+ <p>The <tt>BOOST_CONCEPT_REQUIRES</tt> macro can be used in a function
+ template declaration to check whether some type models a concept. It
+ accepts two arguments, a <strong>list of constraints</strong>, and the
+ function template's return type. The list of constraints takes the form of
+ a sequence of adjacent concept checking template specializations,
+ <strong>in double parentheses</strong>, and the function's return type must
+ also be parenthesized. For example, the standard <code>stable_sort</code>
+ algorithm might be declared as follows: class</p>
+ <pre>
+template<typename RanIter>
+BOOST_CONCEPT_REQUIRES(
+ ((Mutable_RandomAccessIterator<RanIter>))
+ ((LessThanComparable<typename Mutable_RandomAccessIterator<RanIter>::value_type>)),
+ (void)) <font color="green">// return type</font>
+ stable_sort(RanIter,RanIter);
+</pre>
+
+ <p>Note that the algorithm requires that the value type of the iterator be
+ LessThanComparable, and it accesses that value type through the
+ <code>Mutable_RandomAccessIterator</code> concept checking template. In
+ general, the Boost concept checking classes expose associated types as
+ nested member typedefs so that you can use this syntax, which mimics the
+ approach used in the concept support proposed for the next version of
+ C++.</p>
+
+ <h4>Multi-Type Concepts</h4>
+
+ <p>Some concepts deal with more than one type. In this case the
+ corresponding concept checking class will have multiple template
+ parameters. The following example shows how <tt>BOOST_CONCEPT_REQUIRES</tt>
+ is used with the <a href=
+ "../property_map/ReadWritePropertyMap.html">ReadWritePropertyMap</a>
+ concept, which takes two type parameters: a property map and the key type
+ for the map.</p>
+ <pre>
+template <class G, class Buffer, class BFSVisitor,
+ class ColorMap>
+BOOST_CONCEPT_REQUIRES(
+ ((ReadWritePropertyMap<ColorMap, typename IncidenceGraph<G>::vertex_descriptor>)),
+ (void)) <font color="green">// return type</font>
+breadth_first_search(G& g,
+ typename graph_traits<IncidenceGraph>::vertex_descriptor s,
+ Buffer& Q, BFSVisitor vis, ColorMap color)
+{
+ typedef typename IncidenceGraph<G>::vertex_descriptor Vertex;
+ ...
+}
+</pre>
+
+ <p>Although concept checks are designed for use by generic library
+ implementors, they can also be useful to end users. Sometimes one may not
+ be sure whether some type models a particular concept. The syntactic
+ requirements, at least, can easily be checked by creating a small program
+ and using <tt>BOOST_CONCEPT_ASSERT</tt> with the type and concept in
+ question. For example:</p>
+ <pre>
+<font color=
+"green">// Make sure list<int> has bidirectional iterators.</font>
+BOOST_CONCEPT_ASSERT((BidirectionalIterator<std::list<int>::iterator>));
+</pre>
+
+ <p><a href="./concept_check.htm">Prev: Concept Checking
+ Introduction</a><br />
+ <a href="./creating_concepts.htm">Next: Creating Concept Checking
+ Classes</a><br /></p>
+ <hr />
+
+ <table>
+ <tr valign="top">
+ <td nowrap="nowrap">Copyright © 2000</td>
+
+ <td>Jeremy Siek(<a href=
+ "mailto:jsiek_at_[hidden]">jsiek_at_[hidden]</a>) Andrew
+ Lumsdaine(<a href="mailto:lums_at_[hidden]">lums_at_[hidden]</a>), 2007
+ <a href="mailto:dave_at_[hidden]">David Abrahams</a>.</td>
+ </tr>
+ </table>
+</body>
+</html>
Boost-Commit list run by bdawes at acm.org, david.abrahams at rcn.com, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk