Class template format_date

Class template format_date_parser

boost::date_time::format_date_parser — Class with generic date parsing using a format string.

Synopsis

template<typename date_type, typename charT> 
class format_date_parser {
public:
  // types
  typedef std::basic_string< charT >                string_type;          
  typedef std::basic_stringstream< charT >          stringstream_type;    
  typedef std::istreambuf_iterator< charT >         stream_itr_type;      
  typedef string_type::const_iterator               const_itr;            
  typedef date_type::year_type                      year_type;            
  typedef date_type::month_type                     month_type;           
  typedef date_type::day_type                       day_type;             
  typedef date_type::duration_type                  duration_type;        
  typedef date_type::day_of_week_type               day_of_week_type;     
  typedef date_type::day_of_year_type               day_of_year_type;     
  typedef string_parse_tree< charT >                parse_tree_type;      
  typedef parse_tree_type::parse_match_result_type  match_results;        
  typedef std::vector< std::basic_string< charT > > input_collection_type;

  // construct/copy/destruct
  format_date_parser(const string_type &, const input_collection_type &, 
                     const input_collection_type &, 
                     const input_collection_type &, 
                     const input_collection_type &);
  format_date_parser(const string_type &, const std::locale &);
  format_date_parser(const format_date_parser< date_type, charT > &);

  // public member functions
  string_type format() const;
  void format(string_type) ;
  void short_month_names(const input_collection_type &) ;
  void long_month_names(const input_collection_type &) ;
  void short_weekday_names(const input_collection_type &) ;
  void long_weekday_names(const input_collection_type &) ;
  date_type parse_date(const string_type &, const string_type &, 
                       const special_values_parser< date_type, charT > &) const;
  date_type parse_date(std::istreambuf_iterator< charT > &, 
                       std::istreambuf_iterator< charT > &, 
                       const special_values_parser< date_type, charT > &) const;
  date_type parse_date(std::istreambuf_iterator< charT > &, 
                       std::istreambuf_iterator< charT > &, string_type, 
                       const special_values_parser< date_type, charT > &) const;
  month_type parse_month(std::istreambuf_iterator< charT > &, 
                         std::istreambuf_iterator< charT > &, string_type) const;
  month_type parse_month(std::istreambuf_iterator< charT > &, 
                         std::istreambuf_iterator< charT > &, string_type, 
                         match_results &) const;
  day_type parse_day_of_month(std::istreambuf_iterator< charT > &, 
                              std::istreambuf_iterator< charT > &) const;
  day_of_week_type 
  parse_weekday(std::istreambuf_iterator< charT > &, 
                std::istreambuf_iterator< charT > &, string_type) const;
  day_of_week_type 
  parse_weekday(std::istreambuf_iterator< charT > &, 
                std::istreambuf_iterator< charT > &, string_type, 
                match_results &) const;
  year_type parse_year(std::istreambuf_iterator< charT > &, 
                       std::istreambuf_iterator< charT > &, string_type) const;
  year_type parse_year(std::istreambuf_iterator< charT > &, 
                       std::istreambuf_iterator< charT > &, string_type, 
                       match_results &) const;
};

Description

The following is the set of recognized format specifiers

a - Short weekday name
A - Long weekday name
b - Abbreviated month name
B - Full month name
d - Day of the month as decimal 01 to 31
j - Day of year as decimal from 001 to 366
m - Month name as a decimal 01 to 12
U - Week number 00 to 53 with first Sunday as the first day of week 1?
w - Weekday as decimal number 0 to 6 where Sunday == 0
W - Week number 00 to 53 where Monday is first day of week 1
x - facet default date representation
y - Year without the century - eg: 04 for 2004
Y - Year with century

The weekday specifiers (a and A) do not add to the date construction, but they provide a way to skip over the weekday names for formats that provide them.

todo -- Another interesting feature that this approach could provide is an option to fill in any missing fields with the current values from the clock. So if you have m-%d the parser would detect the missing year value and fill it in using the clock.

todo -- What to do with the x. x in the classic facet is just bad...

`format_date_parser` construct/copy/destruct

format_date_parser(const string_type & format, 
                   const input_collection_type & month_short_names, 
                   const input_collection_type & month_long_names, 
                   const input_collection_type & weekday_short_names, 
                   const input_collection_type & weekday_long_names);

format_date_parser(const string_type & format, const std::locale & locale);

format_date_parser(const format_date_parser< date_type, charT > & fdp);

`format_date_parser` public member functions

```
string_type format() const;
```
```
void format(string_type format) ;
```

void short_month_names(const input_collection_type & month_names) ;

void long_month_names(const input_collection_type & month_names) ;

void short_weekday_names(const input_collection_type & weekday_names) ;

void long_weekday_names(const input_collection_type & weekday_names) ;

date_type parse_date(const string_type & value, const string_type & format, 
                     const special_values_parser< date_type, charT > & sv_parser) const;

date_type parse_date(std::istreambuf_iterator< charT > & sitr, 
                     std::istreambuf_iterator< charT > & stream_end, 
                     const special_values_parser< date_type, charT > & sv_parser) const;

date_type parse_date(std::istreambuf_iterator< charT > & sitr, 
                     std::istreambuf_iterator< charT > & stream_end, 
                     string_type format, 
                     const special_values_parser< date_type, charT > & sv_parser) const;

Of all the objects that the format_date_parser can parse, only a date can be a special value. Therefore, only parse_date checks for special_values.

month_type parse_month(std::istreambuf_iterator< charT > & sitr, 
                       std::istreambuf_iterator< charT > & stream_end, 
                       string_type format) const;

month_type parse_month(std::istreambuf_iterator< charT > & sitr, 
                       std::istreambuf_iterator< charT > & stream_end, 
                       string_type format, match_results & mr) const;

day_type parse_day_of_month(std::istreambuf_iterator< charT > & sitr, 
                            std::istreambuf_iterator< charT > & stream_end) const;

day_of_week_type 
parse_weekday(std::istreambuf_iterator< charT > & sitr, 
              std::istreambuf_iterator< charT > & stream_end, 
              string_type format) const;

day_of_week_type 
parse_weekday(std::istreambuf_iterator< charT > & sitr, 
              std::istreambuf_iterator< charT > & stream_end, 
              string_type format, match_results & mr) const;

year_type parse_year(std::istreambuf_iterator< charT > & sitr, 
                     std::istreambuf_iterator< charT > & stream_end, 
                     string_type format) const;

year_type parse_year(std::istreambuf_iterator< charT > & sitr, 
                     std::istreambuf_iterator< charT > & stream_end, 
                     string_type format, match_results & mr) const;