Subject: [Boost-commit] svn:boost r70665 - in trunk: boost/property_tree libs/property_tree/doc libs/property_tree/examples
Date: 2011-03-28 09:33:22
Date: 2011-03-28 09:33:21 EDT (Mon, 28 Mar 2011)
New Revision: 70665
Somewhat improve PTree documentation.
Text files modified:
trunk/boost/property_tree/ptree.hpp | 5 +++--
trunk/libs/property_tree/doc/accessing.qbk | 40 ++++++++++++++++++++++++++++------------
trunk/libs/property_tree/doc/container.qbk | 21 ++++++++++++++-------
trunk/libs/property_tree/doc/json_parser.qbk | 4 ++--
trunk/libs/property_tree/doc/parsers.qbk | 8 ++++----
trunk/libs/property_tree/doc/property_tree.qbk | 4 ++--
trunk/libs/property_tree/doc/synopsis.qbk | 2 +-
trunk/libs/property_tree/doc/xml_parser.qbk | 4 ++--
trunk/libs/property_tree/examples/debug_settings.cpp | 4 ++--
9 files changed, 58 insertions(+), 34 deletions(-)
--- trunk/boost/property_tree/ptree.hpp (original)
+++ trunk/boost/property_tree/ptree.hpp 2011-03-28 09:33:21 EDT (Mon, 28 Mar 2011)
@@ -181,9 +181,9 @@
// Associative view
- /** Returns an iterator to the first child, in order. */
+ /** Returns an iterator to the first child, in key order. */
- /** Returns an iterator to the first child, in order. */
+ /** Returns an iterator to the first child, in key order. */
const_assoc_iterator ordered_begin() const;
/** Returns the not-found iterator. Equivalent to end() in a real
@@ -432,6 +432,7 @@
* return node->get_value_optional();
* return boost::null;
+ * That is, return the value if it exists and can be converted, or nil.
optional<Type> get_optional(const path_type &path) const;
--- trunk/libs/property_tree/doc/accessing.qbk (original)
+++ trunk/libs/property_tree/doc/accessing.qbk 2011-03-28 09:33:21 EDT (Mon, 28 Mar 2011)
@@ -17,7 +17,7 @@
To find the value of `pi` we might do the following:
__ptree__::__ptree_const_iterator__ it = pt.__ptree_find__("pi");
- double pi = boost::lexical_cast<double>(it->second._ptree_data__());
+ double pi = boost::lexical_cast<double>(it->second.__ptree_data__());
This looks quite cumbersome, and would be even more so if `pi` value was not stored so near the top of the tree, and we cared just a little bit more about errors. Fortunately, there is another, correct way of doing it:
@@ -53,26 +53,42 @@
This version uses boost::optional class to handle extraction failure. On successful extraction, it will return boost::optional initialized with extracted value. Otherwise, it will return uninitialized boost::optional.
-To retrieve value from this tree (not some subkey), use __ptree_get_value__, __ptree_get_value__ (default-value version), and __ptree_get_value_optional__. They have identical semantics to __ptree_get__ functions, except they don't take the __path__ parameter. Don't call __ptree_get__ with and empty __path__ to do this as it will try to extract contents of subkey with empty name.
+To retrieve a value from this tree (not some subkey), use __ptree_get_value__, __ptree_get_value__ (default-value version), and __ptree_get_value_optional__. They have identical semantics to __ptree_get__ functions, except they don't take the __path__ parameter. Don't call __ptree_get__ with and empty __path__ to do this as it will try to extract contents of subkey with empty name.
-To use separator character other than default '[^.]', each of the __ptree_get__ versions has another form, which takes an additional parameter in front of path. This parameter of type `char/wchar_t` specifies the separating character. This is a lifesaving device for those who may have dots in their keys:
+To use a separator character other than default '[^.]', you need to construct
+a path object explicitly. The path type for a __ptree__ is a string_path
+instantiation, so the easiest way to refer to it is __ptree__::path_type.
+This way you can use trees that have dots in their keys:
+ typedef ptree::path_type path;
+ pt.get<float>(path("p.a.t.h/t.o/v.a.l.u.e", '/'));
+ pt.get(path("p.a.t.h/t.o/v.a.l.u.e", '/'), 0, NULL);
+ pt.get_optional<std::string>(path("p.a.t.h/t.o/v.a.l.u.e", '/'));
+Note: the special overloads of __ptree_get__ and __ptree_get_optional__ taking
+a separator character that existed in pre-release versions of PropertyTree have
+been removed. This is because the overloads conflicted with using per-call data
- pt.get<float>('/', "p.a.t.h/t.o/v.a.l.u.e");
- pt.get('/', "p.a.t.h/t.o/v.a.l.u.e", 0, NULL);
- pt.get_optional<std::string>('/', "p.a.t.h/t.o/v.a.l.u.e");
+[heading Two Ways of Putting Data]
-[heading One Way of Putting Data]
-To complement __ptree_get__, there is a __ptree_put__ function. Contrary to __ptree_get__, it has only one variant. The reason is, there is no need to handle put failures so often (normally, __ptree_put__ will only fail if conversion of the supplied value to __ptree_data_type__ fails or the system runs out of memory. In the former case, __ptree_put__ will throw __ptree_bad_data__). Sample usage of __ptree_put__ might appear as:
+To complement __ptree_get__, there are __ptree_put__ and __ptree_add__. Contrary to __ptree_get__, they have only one variant each. This is because there is no need to deal with missing values when adding data. If the supplied value cannot be converted to the tree's data type, the functions will throw __ptree_bad_data__.
+ // Overwrites the value
+ pt.__ptree_put__("a.path.to.float.value", 2.72f);
+ // Adds a second node with the new value.
+ pt.__ptree_add__("a.path.to.float.value", 3.14f);
Calling __ptree_put__ will insert a new value at specified path, so that a call to __ptree_get__ specifying the same path will retrieve it. Further, __ptree_put__ will insert any missing path elements during path traversal. For example, calling `__ptree_put__("key1.key2.key3", 3.14f)` on an empty tree will insert three new children: `key1`, `key1.key2` and `key1.key2.key3`. The last one will receive a string `"3.14"` as data, while the two former ones will have empty data strings. __ptree_put__ always inserts new keys at the back of the existing sequences.
+The difference between __ptree_put__ and __ptree_add__ is that put will overwrite existing values if there are any, while add will create a new node to hold the value even if the specified path references an existing node.
-Similar to __ptree_get_value__, there is also a __ptree_put_value__ function. It does the same for this property tree what __ptree_put__ does for its children. Thus, it does not require __path__:
+Similar to __ptree_get_value__, there is also a __ptree_put_value__ function. It does the same for this property tree what __ptree_put__ does for its children. Thus, it does not receive a __path__:
+There is no add_value function.
\ No newline at end of file
--- trunk/libs/property_tree/doc/container.qbk (original)
+++ trunk/libs/property_tree/doc/container.qbk 2011-03-28 09:33:21 EDT (Mon, 28 Mar 2011)
@@ -15,12 +15,19 @@
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.
+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.
-There may be multiple children with the same key value in a node. However, these
-children are not necessarily sequential. The iterator returned by __ptree_find__
-may refer to any of these, and there are no guarantees about the relative
-position of the other equally named 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.
--- trunk/libs/property_tree/doc/json_parser.qbk (original)
+++ trunk/libs/property_tree/doc/json_parser.qbk 2011-03-28 09:33:21 EDT (Mon, 28 Mar 2011)
@@ -10,8 +10,8 @@
The __json__ is a data interchange format derived from the object literal
JSON is a simple, compact format for loosely structured node trees of any depth,
-very similar to the property tree dataset. It is less stuctured than XML and has
-no schema support, but has the advantage of being simpler, smaller and typed
+very similar to the property tree dataset. It is less structured than XML and
+has no schema support, but has the advantage of being simpler, smaller and typed
without the need for a complex schema.
The property tree dataset is not typed, and does not support arrays as such.
--- trunk/libs/property_tree/doc/parsers.qbk (original)
+++ trunk/libs/property_tree/doc/parsers.qbk 2011-03-28 09:33:21 EDT (Mon, 28 Mar 2011)
@@ -14,11 +14,11 @@
-# These parsers will be dropped for now.
+[/ These parsers will be dropped for now.]
+[/ include cmd_line_parser.qbk]
+[/ include windows_registry_parser.qbk]
+[/ include system_environment_parser.qbk]
--- trunk/libs/property_tree/doc/property_tree.qbk (original)
+++ trunk/libs/property_tree/doc/property_tree.qbk 2011-03-28 09:33:21 EDT (Mon, 28 Mar 2011)
@@ -29,7 +29,7 @@
[def __ptree_data_type__ [classref boost::property_tree::basic_ptree::data_type data_type]]
[def __ptree_iterator__ [classref boost::property_tree::basic_ptree::iterator iterator]]
[def __ptree_const_iterator__ [classref boost::property_tree::basic_ptree::const_iterator const_iterator]]
-[def __path__ [classref boost::property_tree::path path]]
+[def __path__ [classref boost::property_tree::string_path path]]
[def __ptree_error__ [classref boost::property_tree::ptree_error ptree_error]]
[def __ptree_bad_data__ [classref boost::property_tree::ptree_bad_data ptree_bad_data]]
[def __ptree_bad_path__ [classref boost::property_tree::ptree_bad_path ptree_bad_path]]
@@ -53,7 +53,7 @@
[def __ptree_get_value_optional__ [memberref boost::property_tree::basic_ptree::get_value_optional get_value_optional]]
[def __ptree_get_child__ [memberref boost::property_tree::basic_ptree::get_child get_child]]
[def __ptree_put__ [memberref boost::property_tree::basic_ptree::put put]]
-[def __ptree_put__ [memberref boost::property_tree::basic_ptree::add add]]
+[def __ptree_add__ [memberref boost::property_tree::basic_ptree::add add]]
[def __ptree_put_value__ [memberref boost::property_tree::basic_ptree::put_value put_value]]
--- trunk/libs/property_tree/doc/synopsis.qbk (original)
+++ trunk/libs/property_tree/doc/synopsis.qbk 2011-03-28 09:33:21 EDT (Mon, 28 Mar 2011)
@@ -28,7 +28,7 @@
functions. These functions allow easy and effective access to the data stored
in property tree. They are various variants of __ptree_get__, __ptree_put__,
__ptree_get_value__, __ptree_put_value__, __ptree_get_child__,
-__ptree_put_child__. Additionally, there is __ptree_data__ function to access
+__ptree_put_child__. Additionally, there is a __ptree_data__ function to access
node data directly.
See the [classref boost::property_tree::basic_ptree basic_ptree class template synopsis] for more information.
--- trunk/libs/property_tree/doc/xml_parser.qbk (original)
+++ trunk/libs/property_tree/doc/xml_parser.qbk 2011-03-28 09:33:21 EDT (Mon, 28 Mar 2011)
@@ -41,8 +41,8 @@
* XML comments are stored in nodes named [^<xmlcomment>], unless comment
ignoring is enabled via the flags.
* Text content is stored in one of two ways, depending on the flags. The default
- way concatenates all text nodes and stores them in a single node called
- [^<xmltext>]. This way, the entire content can be conveniently read, but the
+ way concatenates all text nodes and stores them as the data of the element
+ node. This way, the entire content can be conveniently read, but the
relative ordering of text and child elements is lost. The other way stores
each text content as a separate node, all called [^<xmltext>].
--- trunk/libs/property_tree/examples/debug_settings.cpp (original)
+++ trunk/libs/property_tree/examples/debug_settings.cpp 2011-03-28 09:33:21 EDT (Mon, 28 Mar 2011)
@@ -59,8 +59,8 @@
// child, it throws. Property tree iterator can be used in
// the same way as standard container iterator. Category
// is bidirectional_iterator.
- //BOOST_FOREACH(ptree::value_type &v, pt.get_child("debug.modules"))
- // m_modules.insert(v.second.data());
+ BOOST_FOREACH(ptree::value_type &v, pt.get_child("debug.modules"))
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