/** This class holds constants, symbols with specific numerical value. Each
* object of this class must either provide their own function to evaluate it
* to class numeric or provide the constant as a numeric (if it's an exact
* number). */
class constant : public basic
{
/** This class holds constants, symbols with specific numerical value. Each
* object of this class must either provide their own function to evaluate it
* to class numeric or provide the constant as a numeric (if it's an exact
* number). */
class constant : public basic
{