Added a templated derived exception to KeyNotFound so that you can figure out…

Added a templated derived exception to KeyNotFound so that you can figure out *which* key wasn't found.

include/exceptions.h

@@ -79,6 +79,20 @@ namespace YAML
 			: RepresentationException(line_, column_, ErrorMsg::KEY_NOT_FOUND) {}
 	};
 
+	template <typename T>
+	class TypedKeyNotFound: public KeyNotFound {
+	public:
+		TypedKeyNotFound(int line_, int column_, const T& key_)
+			: KeyNotFound(line_, column_), key(key_) {}
+
+		T key;
+	};
+
+	template <typename T>
+	TypedKeyNotFound <T> MakeTypedKeyNotFound(int line, int column, const T& key) {
+		return TypedKeyNotFound <T> (line, column, key);
+	}
+
 	class BadDereference: public RepresentationException {
 	public:
 		BadDereference()

include/node.h

@@ -119,7 +119,7 @@ namespace YAML
 			}
 		}
 
-		throw KeyNotFound(m_line, m_column);
+		throw MakeTypedKeyNotFound(m_line, m_column, key);
 	}
 
 	template <typename T>

yaml-reader/main.cpp

@@ -11,11 +11,13 @@ void run()
 		YAML::Parser parser(fin);
 		YAML::Node doc;
 		parser.GetNextDocument(doc);
-		for(unsigned i=0;i<doc.size();i++) {
-			bool value;
-			doc[i] >> value;
-			std::cout << (value ? "true" : "false") << "\n";
-		}
+
+		std::cout << "name: " << doc["name"] << "\n";
+		std::cout << "age: " << doc["age"] << "\n";
+	} catch(YAML::TypedKeyNotFound <std::string>& e) {
+		std::cout << "Key '" << e.key << "' not found at line " << e.line+1 << ", col " << e.column+1 << "\n";
+	} catch(YAML::KeyNotFound& e) {
+		std::cout << "Key not found at line " << e.line+1 << ", col " << e.column+1 << "\n";
 	} catch(YAML::Exception& e) {
 		std::cout << "Error at line " << e.line+1 << ", col " << e.column+1 << ": " << e.msg << "\n";
 	}

yaml-reader/tests/test.yaml

-- true
-- n
-- Off
-- YES
+name: Brett Favre
+position: QB
+teams: [ Falcons, Packers, Jets ]
\ No newline at end of file
-- on
-- FALSE
-- FaLse