1 files changed, 39 insertions, 53 deletions

diff --git a/libs/property_tree/examples/debug_settings.cpp b/libs/property_tree/examples/debug_settings.cpp
index 639155608..2684f4359 100644
--- a/libs/property_tree/examples/debug_settings.cpp
+++ b/libs/property_tree/examples/debug_settings.cpp
@@ -8,6 +8,7 @@
 // For more information, see www.boost.org
 // ----------------------------------------------------------------------------
 
+//[debug_settings_includes
 #include <boost/property_tree/ptree.hpp>
 #include <boost/property_tree/xml_parser.hpp>
 #include <boost/foreach.hpp>
@@ -15,7 +16,9 @@
 #include <set>
 #include <exception>
 #include <iostream>
-
+namespace pt = boost::property_tree;
+//]
+//[debug_settings_data
 struct debug_settings
 {
     std::string m_file;               // log filename
@@ -24,80 +27,63 @@ struct debug_settings
     void load(const std::string &filename);
     void save(const std::string &filename);
 };
-
+//]
+//[debug_settings_load
 void debug_settings::load(const std::string &filename)
 {
-
     // Create empty property tree object
-    using boost::property_tree::ptree;
-    ptree pt;
+    pt::ptree tree;
 
-    // Load XML file and put its contents in property tree. 
-    // No namespace qualification is needed, because of Koenig 
-    // lookup on the second argument. If reading fails, exception
-    // is thrown.
-    read_xml(filename, pt);
+    // Parse the XML into the property tree.
+    pt::read_xml(filename, tree);
 
-    // Get filename and store it in m_file variable. Note that 
-    // we specify a path to the value using notation where keys 
-    // are separated with dots (different separator may be used 
-    // if keys themselves contain dots). If debug.filename key is 
-    // not found, exception is thrown.
-    m_file = pt.get<std::string>("debug.filename");
-    
-    // Get debug level and store it in m_level variable. This is 
-    // another version of get method: if debug.level key is not 
-    // found, it will return default value (specified by second 
-    // parameter) instead of throwing. Type of the value extracted 
-    // is determined by type of second parameter, so we can simply 
-    // write get(...) instead of get<int>(...).
-    m_level = pt.get("debug.level", 0);
+    // Use the throwing version of get to find the debug filename.
+    // If the path cannot be resolved, an exception is thrown.
+    m_file = tree.get<std::string>("debug.filename");
 
-    // Iterate over debug.modules section and store all found 
-    // modules in m_modules set. get_child() function returns a 
-    // reference to child at specified path; if there is no such 
-    // 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"))
+    // Use the default-value version of get to find the debug level.
+    // Note that the default value is used to deduce the target type.
+    m_level = tree.get("debug.level", 0);
+
+    // Use get_child to find the node containing the modules, and iterate over
+    // its children. If the path cannot be resolved, get_child throws.
+    // A C++11 for-range loop would also work.
+    BOOST_FOREACH(pt::ptree::value_type &v, tree.get_child("debug.modules")) {
+        // The data function is used to access the data stored in a node.
         m_modules.insert(v.second.data());
+    }
 
 }
-
+//]
+//[debug_settings_save
 void debug_settings::save(const std::string &filename)
 {
+    // Create an empty property tree object.
+    pt::ptree tree;
 
-    // Create empty property tree object
-    using boost::property_tree::ptree;
-    ptree pt;
-
-    // Put log filename in property tree
-    pt.put("debug.filename", m_file);
-
-    // Put debug level in property tree
-    pt.put("debug.level", m_level);
+    // Put the simple values into the tree. The integer is automatically
+    // converted to a string. Note that the "debug" node is automatically
+    // created if it doesn't exist.
+    tree.put("debug.filename", m_file);
+    tree.put("debug.level", m_level);
 
-    // Iterate over modules in set and put them in property
-    // tree. Note that the add function places new key at the
-    // end of list of keys. This is fine in most of the
-    // situations. If you want to place item at some other
-    // place (i.e. at front or somewhere in the middle),
-    // this can be achieved using a combination of the insert
-    // and put_value functions
+    // Add all the modules. Unlike put, which overwrites existing nodes, add
+    // adds a new node at the lowest level, so the "modules" node will have
+    // multiple "module" children.
     BOOST_FOREACH(const std::string &name, m_modules)
-        pt.add("debug.modules.module", name);
-    
-    // Write property tree to XML file
-    write_xml(filename, pt);
+        tree.add("debug.modules.module", name);
 
+    // Write property tree to XML file
+    pt::write_xml(filename, tree);
 }
+//]
 
 int main()
 {
     try
     {
         debug_settings ds;
-        ds.load("debug_settings.xml");
+        ds.load("debug_settings_xml");
         ds.save("debug_settings_out.xml");
         std::cout << "Success\n";
     }