Boost C++ Libraries

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Class value_semantic

boost::program_options::value_semantic —

Synopsis

class value_semantic {
public:
  // construct/copy/destruct
  ~value_semantic();

  // public member functions
  virtual std::string name() const;
  virtual bool is_zero_tokens() const;
  virtual bool is_composing() const;
  virtual bool is_implicit() const;
  virtual bool is_multitoken() const;
  virtual void 
  parse(boost::any &, const std::vector< std::string > &, bool) const;
  virtual bool apply_default(boost::any &) const;
  virtual void notify(const boost::any &) const;
};

Description

Class which specifies how the option's value is to be parsed and converted into C++ types.

value_semantic construct/copy/destruct

  1. ~value_semantic();

value_semantic public member functions

  1. virtual std::string name() const;

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

  2. virtual bool is_zero_tokens() const;

    Returns true if value cannot be specified in source at all. Other methods can still set the value somehow, but user can't affect it. 

  3. 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. 

  4. virtual bool is_implicit() const;

    Returns true if explicit value of an option can be omitted. 

  5. virtual bool is_multitoken() const;

    Returns true if value can span several token in input source. 

  6. 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. 

  7. 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. 

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

    Called when final value of an option is determined.

Copyright © 2002-2004 Vladimir Prus
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