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Class value_semantic

boost::program_options::value_semantic —


class value_semantic {
// construct/copy/destruct

// 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;


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