Value, bValue and tmValue

In Value.h, there are three classes: Value, bValue and tmValue. Value is the base abstract class for the other two classes. Value has two virtual functions: Clone() makes a copy, STR() returns a string of a derived class's status.

class Value {
protected:
    Value(){}
public:
    virtual Value* Clone() const {return NULL;}
    virtual string STR() const {return string(); }
};

bValue is a concrete class derived from Value. bValue is a template class, and it has a field v whose type is the template augment V. Thus we can define bValue<bool>, bValue<char>, bValue<int>, bValue<double> whose value types are bool, char, int, and double, respectively.

template<class V>
class bValue: public Value {
public:
    V v;  //-- public value field
    ...
};

tmValue is a concrete class derived from Value. This class has a map from a string to a double-precision floating number that can be used to identify an event as a string and to specify its occurrence time.

class tmValue: public Value {
public:
    map<string, double> TimeMap;
    ...
};

You can see how to use this tmValue in Section 4.2.1 and 4.3.