| [/ |
| / Copyright (c) 2008 Marcin Kalicinski (kalita <at> poczta dot onet dot pl) |
| / Copyright (c) 2009 Sebastian Redl (sebastian dot redl <at> getdesigned dot at) |
| / |
| / 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) |
| /] |
| [section:container Property Tree as a Container] |
| [/ __ptree_*__ macros expected from property_tree.qbk] |
| Every property tree node models the ReversibleSequence concept, providing |
| access to its immediate children. This means that iterating over a __ptree__ |
| (which is the same as its root node - every __ptree__ node is also the |
| subtree it starts) iterates only a single level of the hierarchy. There is no |
| way to iterate over the entire tree. |
| |
| It is very important to remember that the property sequence is *not* ordered by |
| the key. It preserves the order of insertion. It closely resembles a std::list. |
| Fast access to children by name is provided via a separate lookup structure. Do |
| not attempt to use algorithms that expect an ordered sequence (like |
| binary_search) on a node's children. |
| |
| The property tree exposes a second container-like interface, called the |
| associative view. Its iterator type is the nested type assoc_iterator (and its |
| const counterpart const_assoc_iterator). You can get an ordered view of all |
| children by using ordered_begin() and ordered_end(). |
| |
| The associative view also provides find() and equal_range() members, which |
| return assoc_iterators, but otherwise have the same semantics as the members |
| of std::map of the same name. |
| |
| You can get a normal iterator from an assoc_iterator by using the to_iterator() |
| member function. Converting the other way is not possible. |
| [endsect] [/container] |
