~value_semantic();

virtual std::string name() const;

Returns the name of the option. The name is only meaningful for automatic help message.

virtual unsigned min_tokens() const;

The minimum number of tokens for this option that should be present on the command line.

virtual unsigned max_tokens() const;

The maximum number of tokens for this option that should be present on the command line.

virtual bool is_composing() const;

Returns true if values from different sources should be composed. Otherwise, value from the first source is used and values from other sources are discarded.

virtual void 
parse(boost::any & value_store, const std::vector< std::string > & new_tokens, 
      bool utf8) const;

Parses a group of tokens that specify a value of option. Stores the result in 'value_store', using whatever representation is desired. May be be called several times if value of the same option is specified more than once.

virtual bool apply_default(boost::any & value_store) const;

Called to assign default value to 'value_store'. Returns true if default value is assigned, and false if no default value exists.

virtual void notify(const boost::any & value_store) const;

Called when final value of an option is determined.