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Boost.Range documentation iteration.

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[SVN r61660]
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Neil Groves
2010-04-28 19:07:47 +00:00
parent 83c89f3038
commit 1d5fb47238
111 changed files with 525 additions and 2192 deletions
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71
doc/introduction.qbk
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@ -12,62 +12,27 @@ The main advantages are
* more flexible, compact and maintainable client code
* safe use of built-in arrays (for legacy code; why else would you use built-in arrays?)
Below are given a small example (the complete example can be found [@http://www.boost.org/libs/range/test/algorithm_example.cpp here] ):
[heading Example - Iterate over the values in a map]
``
//
// example: extracting bounds in a generic algorithm
//
template< class ForwardReadableRange, class T >
inline typename boost::range_iterator< ForwardReadableRange >::type
find( ForwardReadableRange& c, const T& value )
{
return std::find( boost::begin( c ), boost::end( c ), value );
}
template< class ForwardReadableRange, class T >
inline typename boost::range_iterator< const ForwardReadableRange >::type
find( const ForwardReadableRange& c, const T& value )
{
return std::find( boost::begin( c ), boost::end( c ), value );
}
//
// replace first value and return its index
//
template< class ForwardReadableWriteableRange, class T >
inline typename boost::range_size< ForwardReadableWriteableRange >::type
my_generic_replace( ForwardReadableWriteableRange& c, const T& value, const T& replacement )
{
typename boost::range_iterator< ForwardReadableWriteableRange >::type found = find( c, value );
if( found != boost::end( c ) )
*found = replacement;
return std::distance( boost::begin( c ), found );
}
//
// usage
//
const int N = 5;
std::vector<int> my_vector;
int values[] = { 1,2,3,4,5,6,7,8,9 };
my_vector.assign( values, boost::end( values ) );
typedef std::vector<int>::iterator iterator;
std::pair<iterator,iterator> my_view( boost::begin( my_vector ),
boost::begin( my_vector ) + N );
char str_val[] = "a string";
char* str = str_val;
std::cout << my_generic_replace( my_vector, 4, 2 );
std::cout << my_generic_replace( my_view, 4, 2 );
std::cout << my_generic_replace( str, 'a', 'b' );
// prints '3', '5' and '0'
using namespace boost;
using namespace boost::adaptors;
for_each( my_map | map_values, fn );
``
By using the free-standing functions and __metafunctions__, the code automatically works for all the types supported by this library; now and in the future. Notice that we have to provide two versions of `find()` since we cannot forward a non-const rvalue with reference arguments (see this article about __the_forwarding_problem__ ).
[heading Example - Iterate over the keys in a map]
``
using namespace boost;
using namespace boost::adaptors;
for_each( my_map | map_keys, fn );
``
[heading Example - Push the even values from a map in reverse order into the container `target`]
``
using namespace boost;
using namespace boost::adaptors;
// Assume that is_even is a predicate that has been implemented elsewhere...
push_back(target, my_map | map_values | filtered(is_even()) | reversed);
``
[endsect]