Provided by: libdate-manip-perl_6.42-1_all bug

NAME

       Date::Manip::Date - Methods for working with dates

SYNOPSIS

          use Date::Manip::Date;
          $date = new Date::Manip::Date;

DESCRIPTION

       This module works specifically with date objects.

       Although the word date is used extensively here, it is actually somewhat misleading.
       Date::Manip works with the full calendar date (year, month, day, and week when
       appropriate), time of day (hour, minute, second), and time zone.  It doesn't work with
       fractional seconds.

METHODS

       base
       config
       err
       is_date
       is_delta
       is_recur
       new
       new_config
       new_date
       new_delta
       new_recur
       tz  Please refer to the Date::Manip::Obj documentation for these methods.

       calc
              $date2 = $date->calc($delta [,$subtract]);
              $delta = $date->calc($date2 [,$subtract] [,$mode]);

           Please refer to the Date::Manip::Calc documentation for details.

       cmp
              $val = $date1->cmp($date2);

           This compares two different dates (both of which must be valid date objects). It
           returns -1, 0, or 1 similar to the cmp or <=> operators in perl. The comparison will
           automatically handle time zone differences between the two dates (i.e. they will be
           sorted in order as they appear in the GMT zone).

           A warning is printed if either of the date objects does not include a valid date.

       complete
              $flag = $date->complete([$field]);

           This tests the date stored in the object to see if it is complete or truncated (see
           below for a discussion of this).

           If no $field is passed in, it returns 1 if the date is complete, or 0 if it was
           truncated and default values have been supplied.

           If $field is passed in, it may be one of: m, d, h, mn, s . It will return 1 if the
           value for that field was specified, or 0 if a default was used.

       convert
              $err = $date->convert([$zone]);

           This converts the date stored in the object to a different time zone.  $zone can be
           the name of a time zone. If it is not passed in, the date is converted to the local
           time zone.

       holiday
              $name = $date->holiday();
              @name = $date->holiday();
              $name = $date->event();

           This returns the name of the holiday if $date is a holiday. If $date is not a holiday,
           undef is returned. If $date is an unnamed holiday, an empty string is returned.

           In scalar context, holiday returns the name of one holiday that occurs on that date
           (the one first defined in the config file).  In list context, it returns all holidays
           on that date.

       input
              $str = $date->input();

           This returns the string that was parsed to form the date.

       is_business_day
              $flag = $date->is_business_day($checktime);

           This returns 1 if $date is a business day.

           $checktime may be passed in. If it is non-zero, the time is checked to see if the date
           is a business day and falls within work hours.

       list_holidays
             @date = $date->list_holidays([$y]);

           This returns a list of Date::Manip::Date objects containing all dates during a year
           which are holidays. The times will all be 00:00:00.

           If $y is not passed in, it will list the holidays in the same year as the date stored
           in $date.

       list_events
              @list = $date->list_events(       [$format] );
              @list = $date->list_events(0      [,$format]);
              @list = $date->list_events($date1 [,$format]);

           This returns a list of events.  Events are defined in the Events section of the config
           file (discussed in the Date::Manip::Holidays manual).

           In the first form, a list of all events active at the precise time stored in $date
           will be returned.

           If the first argument evaluates to 0, a list of all events active at any time during
           that day (Y,M,D) are returned.

           If the first argument is another date object, all events that are active at any time
           between the two dates (inclusive) are returned.

           By default, the list returned is of the form:

              ( [START, END, NAME],
                [START, END, NAME],
                ...
              )

           where START is a date object when an event starts, END is a date object when it ends,
           and NAME is the name of the event. Note that START and END are the actual start and
           end date of the event and may be outside the range of dates being examined (though the
           event will obviously overlap the range or it wouldn't be included in the list).

           If $format is included, it can specify an alternate format for the output. Currently,
           the only supported format is named "dates" and it returns a list in the form:

              ( [DATE1, NAME1a, NAME1b, ...],
                [DATE2, NAME2a, NAME2b, ...],
                ...
              )

           This includes a list of all dates during the range when there is a change in what
           events are active. DATE1 will always be the start of the range being considered, and
           (NAME1a, NAME1b, ...) are the list of all events that will be active at that time. At
           DATE2, the list of active events changes with (NAME2a, NAME2b, ...) being active.

           It is quite possible that a date be included which has no active events, and in that
           case, the list of names will be empty.

       nearest_business_day
              $date->nearest_business_day([$tomorrowfirst]);

           This looks for the work day nearest to $date.  If $date is a work day, it is left
           unmodified.  Otherwise, it will look forward or backwards in time 1 day at a time
           until a work day is found.  If $tomorrowfirst is non-zero (or if it is omitted and the
           config variable TomorrowFirst is non-zero), we look to the future first.  Otherwise,
           we look in the past first.  In other words, in a normal week, if $date is Wednesday,
           $date is returned.  If $date is Saturday, Friday is returned.  If $date is Sunday,
           Monday is returned.  If Wednesday is a holiday, Thursday is returned if $tomorrowfirst
           is non-nil or Tuesday otherwise.

       next_business_day
       prev_business_day
              $date->next_business_day($off [,$checktime]);
              $date->prev_business_day($off [,$checktime]);

           The next_business_day method sets the given date to $off (which can be a positive
           integer or zero) business days in the future. The prev_business_day method sets the
           date to $off business days in the past.

           First, $date is tested. If $checktime is nonzero, the date must fall on a business
           date, and during business hours. If $checktime is zero, the time check is not done,
           and the date must simply fall on a business date.

           If the check fails, the date is moved to the start of the next business day (if
           $checktime is nonzero) or the next business day at the current time (if $checktime is
           zero). Otherwise, it is left unmodified.

           Next, if $off is greater than 0, the day $off work days from now is determined.

           One thing to note for the prev_business_day method is that if $date check fails, the
           date is set to the next business date, exactly like next_business_day. In other words,
           if $date is not a business day, the call:

              $date->prev_business_day(0 [,$checktime]);

           moves $date forward in time instead of backward which is nonintuitive, but you just
           have to think of day 0 as being the next business day if $date is not a business day.

           As a result, the following two calls ALWAYS give the same result:

              $date->next_business_day(0 [,$checktime]);
              $date->prev_business_day(0 [,$checktime]);

           no matter what date is stored in $date.

       parse
              $err = $date->parse($string [,@opts]);

           This parses a string which should include a valid date and stores it in the object. If
           the string does not include a valid date, an error is returned. Use the err method to
           see the full error message.

           A full date may include a calendar date (year, month, day), a time of day (hour,
           minute, second), and time zone information. All of this can be entered in many
           different formats.

           For information on valid date formats, refer to the section VALID DATE FORMATS. For
           information on valid time zone information, refer to the section VALID TIME ZONE
           FORMATS.

           If no time zone information is included in the date, it is treated as being in the
           local time zone.

           If time zone information is included, the date will be kept in that time zone, and all
           operations will be done in that time zone.  The convert method can be used to change
           the time zone to the local time zone, or to another time zone.

           Some things to note:

           All strings are case insensitive.  "December" and "DEceMBer" are equivalent.

           When a part of the date is not given, defaults are used. This is described below in
           the section "Complete vs. truncated dates and times".

           The year may be entered as 2 or 4 digits.  If entered as 2 digits, it will be
           converted to a 4 digit year.  There are several ways to do this based on the value of
           the YYtoYYYY config variable.  Refer to the Date::Manip::Config documentation for more
           details.

           Dates are always checked to make sure they are valid.

           If any other arguments are passed in, they act as options which may improve the speed
           of parsing. These include:

              noiso8601  Do not try to parse the
                         date as an ISO 8601 date
                         or time.
              nodow      Do not try to parse a
                         day-of-week (Monday) in
                         the string.
              nocommon   Do not try to parse the
                         date using the formats
                         in the "Common date
                         formats" section.
              noother    Do not try to parse the
                         date using the "Less common
                         date formats" or a time
                         using the "Other time
                         formats".
              nospecial  Do not try to parse the
                         date using the "Special
                         date strings" formats
                         or a time using the
                         "Special time strings"
                         formats, or as a
                         combined date/time using
                         the "Additional combined
                         date and time" formats.
              nodelta    Do not treat deltas as
                         a date relative to now.
              noholidays Do not parse holiday
                         names as dates.

       parse_date
              $err = $date->parse_date($string [,@opts]);

           This parses a string which contains a valid date and sets the date part of the object.

           If the object contained a valid date, the time is kept unchanged. If the object did
           NOT contain a valid date, a time of 00:00:00 is used.

           @opts can be any of the strings described in the parse method above.

       parse_time
              $err = $date->parse_time($string);

           This parses a string and sets the time portion of $date to contain it.

           If the object contained a valid date, the Y/M/D portion is left unchanged.  Otherwise,
           the current date is used.

       parse_format
              $err = $date->parse_format($format,$string);

           This will parse a date contained in $string based on explicit format information
           contained in $format.

           If the format is invalid, $err will contain an error message.  If the format is valid,
           but string doesn't match, an error code of 1 is returned.

           $format is a string containing a regular expression with some special directives
           (based on the printf directives). These directives are turned into regular expression
           components, and then the entire string is turned into a regular expression which, if
           $string matches it, will return the date.

           The directives available are identical to the printf directives. So, if your $format
           string contains the directive '%Y', it will match a 4-digit year.

           All of the printf directives are available, but with a few simplifications:

              %l        This directive is NOT available.

              %b,%h,%B  will all match a month name or
                        abbreviation

              %v,%a,%A  will all match a day abbreviation
                        or name

              %z,%Z,%N  will match any time zone string

              %n        currently not allowed (multi-line
                        matching not currently supported)

           The format string may not over-specify the date. In other words, you may not include
           both a %y and %Y directive or both a %j and %m directive.

           A valid format string will specify any of the following sets of data:

              Required          Optional

              M D H Mn S        Y Zone Day-of-week
              M D H Mn          Y Zone Day-of-week
              M D               Y Zone Day-of-week
              H Mn S            Zone
              H Mn              Zone

           For example, if you had a date stored as:

              YYYY.MM-DD

           you could match it using the following:

              $date->parse_format('%Y\\.%m\\-%d',$string);

           If you wanted to extract the date from an apache log line:

              10.11.12.13 - - [17/Aug/2009:12:33:30 -0400] "GET /favicon.ico ...

           you could use:

              $date->parse_format('.*?\\[%d/%b/%Y:%T %z\\].*',$line);

           When matching months, days, and hours, there are two directives that could be used
           (for numerical versions).  For the month, you may use %m or %f.  If your date is known
           to have a two-digit month, you should use %m.  If it contains a one- or two-digit
           month, you must use %f (and it is safe to use %f for two-digit months).  Similarly,
           for days, you can use %d or %e and for hours you can use %H or %k.  In both cases, the
           first can only be used if you are guaranteed a 2-digit value.

           In your format string, you may use capture buffers that can be back referenced
           elsewhere in the regular expression. If you use numbered back references, just be
           aware that all of the directives create a single capture buffer (except for the
           directives like %% which match a special character instead of a portion of a date). If
           you use named buffers, do NOT use any of the following as they will conflict with the
           capture buffers created with the standard directives:

              y
              m
              d
              h
              mn
              s
              mon_name
              mon_abb
              dow_name
              dow_abb
              dow_char
              dow_num
              doy
              nth
              ampm
              epochs
              epocho
              tzstring
              off
              abb
              zone
              g
              w
              l
              u

           To be safe, it is suggested that named capture buffers start with a capital letter.

           There is one other caveat if the %x directive is used. The format is converted to a
           regular expression and then cached (so that a format can be reused without the penalty
           of doing the conversion to a regular expression, so if you need to set the DateFormat
           config variable (which determines the meaning of the %x directive), it must be done
           before a format string containing %x is used. If the DateFormat config variable is set
           afterwards, the format string will reflect the old, NOT THE NEW, value of DateFormat.

       prev
       next
           The prev method changes the date to the previous (or current) occurrence of either a
           day of the week, a certain time of day, or both. The next method changes the date to
           the next (or current) occurrence. The examples below illustrate the prev method, but
           the next one is identical in operation.

           There are two different ways to use this method. The first is to pass in a day of week
           and possibly a time:

              $err = $date->prev($dow, $curr [,$time]);

           If $curr = 0, this means to look for the previous occurence of the day of week, and
           set the time to the value passed in (or current time if no time was passed in). The
           day is ALWAY less than the current day. If the current day is the same day of week as
           $dow, then the date returned will be one week earlier.

           If $curr = 1, it means to look for the current or previous occurence of the day of
           week, and set the time to the value passed in (or 00:00:00 if none was passed in). If
           the current day of week is the same as $dow, the date will remain unchanged. Since the
           time is then set, the new date may actually occur after the original date depending on
           the value of $time.

           If $curr = 2, it means to look for the last time (not counting now) that the day of
           week at the given time occurred. The date may be the same as the original date.

           $time may be a list reference of [H,MN,S], [H,MN], or [H].

           The following examples should illustrate the use of this function.

               Original Date = Fri Nov 22 18:15:00

               dow      curr   time       new date

               4 (Thu)  0/1/2  undef      Thu Nov 21 00:00:00
               4        0/1/2  [12,30,0]  Thu Nov 21 12:30:00

               5 (Fri)  0/2    undef      Fri Nov 15 18:15:00
               5        1      undef      Fri Nov 22 18:15:00

               5        0      [12,30,0]  Fri Nov 15 12:30:00
               5        1/2    [12,30,0]  Fri Nov 22 12:30:00

               5        0/2    [19,30,0]  Fri Nov 15 19:30:00
               5        1      [19,30,0]  Fri Nov 22 19:30:00

           The second way to use this method is by passing in undef for the day of week.

              $err = $date->prev(undef,$curr,$time);

           In this case, a time is required and it must be a list reference of 3 elements: [H,
           MN, S]. Any or all of the elements may be undef.

           The new date is the previous occurrence of the time.

           If you define hours, then minutes and seconds may be defined, or default to 0 and you
           are looking for a previous time that the specified time (HH:00:00) occurred (which
           might be as much as 24 hours in the past).

           If hours are undefined and minutes are defined, then seconds may be defined, or
           default to 0, and you are looking for the last time the minutes/seconds (MN:SS)
           appeared on the digital clock, which will be sometime in the past hour.

           Finally, if hours and minutes are undefined, seconds must be defined (or default to
           zero) and the last time that that second occurred will be returned (which will be
           sometime in the past minute).

           If $curr is non-zero, the current time is returned if it matches the criteria passed
           in, so the returned value will be now or in the past.  If $curr is zero, the time
           returned will definitely be in the past.

               DATE = Fri Nov 22 18:15:00

               curr  hr     min    sec      returns
               0/1   18     undef  undef    Nov 22 18:00:00
               0/1   18     30     0        Nov 21 18:30:00
               0     18     15     undef    Nov 21 18:15:00
               1     18     15     undef    Nov 22 18:15:00
               0     undef  15     undef    Nov 22 17:15:00
               1     undef  15     undef    Nov 22 18:15:00

       printf
              $out = $date->printf($in);
              @out = $date->printf(@in);

           This takes a string or list of strings which may contain any number of special
           formatting directives. These directives are replaced with information contained in the
           date. Everything else in the string is returned unmodified.

           A directive always begins with '%'. They are described in the section below in the
           section PRINTF DIRECTIVES.

       secs_since_1970_GMT
              $secs = $date->secs_since_1970_GMT();

           This returns the number of seconds that have elapsed since Jan 1, 1970 00:00:00 GMT
           (negative if the date is earlier).

           The reverse is also allowed:

              $err = $date->secs_sincs_1970_GMT($secs);

           which sets the date to $secs seconds from Jan 1, 1970 00:00:00 GMT in the local time
           zone.

       set
              $err = $date->set($field,@vals [,$isdst]);

           This explicitly sets one or more fields in a date.

           $field can be any of the following:

              $field   @vals

              zone     [ZONE]         ZONE can be any zone or alias

              zdate    [ZONE,]DATE    sets the zone and entire date

              date     DATE           sets the entire date

              time     TIME           sets the entire time

              y        YEAR           sets one field
              m        MONTH
              d        DAY
              h        HOUR
              mn       MINUTE
              s        SECOND

           Here, DATE is a list reference containing [Y,M,D,H,MN,S] and TIME is a list reference
           containing [H,MN,S].

           ZONE is optional (it defaults to the local zone as defined either by the system clock,
           or the SetDate or ForceDate config variables). If it is passed in, it can be any zone
           name, abbreviation, or offset. An offset can be expressed either as a valid offset
           string, or as a list reference.  Refer to the join/split functions of
           Date::Manip::Base for information on valid offset strings.

           An optional last argument is $isdst (which must be 0 or 1) is included when setting a
           date which could be in either standard time or daylight saving time. It is ignored in
           all other situations. If it is not included, and the resulting date could be in
           either, it will default to standard time.

           The $date object must contain a valid date (unless the entire date is being set with
           $field set to either "zdate" or "date").

           If $field is "zone", the time zone of the date will be set. If ZONE is not passed in,
           it will be set to the local time zone.  When setting the time zone, no conversion is
           done! Whatever date and time is stored in the $date object prior to this remains
           unchanged... except it will be that date and time in the new time zone.

           If $field is "zdate", the entire date and time zone is set. If ZONE is not passed in,
           it is set to the local time zone.

           If $field is "date", the entire date will be set, but the time zone of the date will
           not be changed.

           If $field is "time", or one of the individual fields, only those fields will be
           modified.

           An error is returned if an invalid argument list is passed in, or if the resulting
           date is checked and found to be invalid.

       value
              $val = $date->value([$type]);
              @val = $date->value([$type]);

           These return the value of the date stored in the object.

           In scalar context, a printable string in the form YYYYMMDDHH:MN:SS is returned. In
           list context, a list is returned of (Y,M,D,H,MN,S).

           If $type is omitted, the date is returned in the time zone it was parsed in.

           If $type is "local", it is returned in the local time zone (which is either the system
           time zone, or the zone specified with the SetDate or ForceDate config variables).

           If $type is "gmt", the date is returned in the GMT time zone.

           An empty string or list is returned i the case of an error (and an error code is set).

       week_of_year
              $wkno = $date->week_of_year([$first]);

           This figures out the week number. If $first is passed in, it must be between 1 and 7
           and refers to the first day of the week. If $first is not passed in, the FirstDay
           config variable is used.

           NOTE: This routine should only be called in rare cases.  Use printf with the %W, %U,
           %J, %L formats instead.  This routine returns a week between 0 and 53 which must then
           be "fixed" to get into the ISO 8601 weeks from 1 to 53.  A date which returns a week
           of 0 actually belongs to the last week of the previous year.  A date which returns a
           week of 53 may belong to the first week of the next year.

ISSUES WITH PARSING DATES

       The following issues may occur when parsing dates that should be understood to make full
       use of this module.

       Complete vs. truncated dates and times
           Date formats are either complete or truncated. A complete date fully specifies the
           year, month, and day and a complete time fully specifies the hour, minute, and second.

           It should be understood that in many instances, the information may be implied rather
           than explicitly stated, but it is still treated as complete.

           For example, the date "January 3" is complete because it implies the current year.

           A truncated calendar date or time does not include information about some of the
           fields. Date::Manip will never work with a partial date or time, so defaults will be
           supplied.

           For example, the date "2009-01" is missing a day field, so a default will be used. In
           this case, the day will be the 1st, so this is equivalent to "Jan 1st 2009". If only
           the year is given, it will default to Jan 1.

           If the time, or any of it's components is missing, they default to 00. So the time
           "12:30" and "12:30:00" are equivalent.

           The "complete" method can be used to check what type of date was parsed, and which
           values were specified (either explicitly or implied) and which were provided as a
           default. It should be noted that there is no way to differentiate between an explicit
           and implied value.

           A string with a date and/or time may consist of any of the following:

              a complete date and a time (complete or truncated)
              a truncated date with no time
              a time (complete or truncated) with no date

           In other words, the date "Jan 2009 12:30" is not valid since it consists of a time
           with a truncated date.

VALID TIME ZONE FORMATS

       When specifying a time zone, it can be done in three different ways.  One way is to
       specify the actual time zone. The second is to supply a valid time zone abbreviation. The
       third is to specify an offset (with an optional abbreviation). The following dates
       illustrate the these formats.

       The timezone information always follows the time immediately, and may only be included if
       a time is included. The following examples use an ISO 8601 format for the date/time, but
       any of the other date and time formats may be used.

       The first way to specify the time zone is to specify it by complete name (or using one of
       the standard aliases):

          2001-07-01-00:00:00 America/New_York

       Although this is unambiguous when it comes to determining the time zone, the time is
       ambiguous in most zones for one hour of the year. When a time change occurs during which
       the clock is moved back, the same wallclock time occurs twice.

       For example, in America/New_York, on Sunday, Nov 2, 2008, at 02:00 in the morning, the
       clock was set back to 01:00. As a result, the date Nov 2, 2008 at 01:30 is ambiguous. It
       is impossible to determine if this refers to the 01:30 that occurred half an hour before
       the time change, or the one 30 minute after the change.

       In practice, if this form is used, the date will be assigned to standard time, meaning
       that there will be some times (typically 1 hour per year) which cannot be expressed this
       way. As such, this method is discouraged.

       The second way to specify the time zone, which is the most common, is to use a time zone
       abbreviation:

          2001-07-01-00:00:00 EDT

       Unfortunately, the abbreviation does not uniquely determine the time zone except in a few
       cases. In order to assign a time zone, Date::Manip will refer to a list of all time zones
       which use the abbreviation.  They will be tested, in the order given in the
       Date::Manip::Zones documentation, and the first match (i.e. the one in which the given
       date/time and abbreviation are valid) determines the time zone which will be used. A great
       deal of effort has been made to ensure that the most likely time zone will be obtained
       (i.e. the most common time zones are tested before less common ones), so in most cases,
       the desired results will be obtained.

       If the default order does not yield the desired time zone, the order of testing can be
       modified using the abbrev method described in the Date::Manip::TZ documentation.

       Although the time zone is ambiguous, the date is not, since only time zones for which the
       date are valid will be used.

       The third way to specify the time zone is by specifying an offset and an optional
       abbreviation:

          2001-07-01-00:00:00 -04
          2001-07-01-00:00:00 -0400
          2001-07-01-00:00:00 -040000
          2001-07-01-00:00:00 -04:00
          2001-07-01-00:00:00 -04:00:00

          2001-07-01-00:00:00 -04 (EDT)
          2001-07-01-00:00:00 -0400 (EDT)
          2001-07-01-00:00:00 -040000 (EDT)
          2001-07-01-00:00:00 -04:00 (EDT)
          2001-07-01-00:00:00 -04:00:00 (EDT)

          2001-07-01-00:00:00 -04 EDT
          2001-07-01-00:00:00 -0400 EDT
          2001-07-01-00:00:00 -040000 EDT
          2001-07-01-00:00:00 -04:00 EDT
          2001-07-01-00:00:00 -04:00:00 EDT

       The offset almost never sufficient to uniquely determine the time zone (and it is not even
       guaranteed that both the offset and abbreviation will, though in practice, it is probably
       sufficient). In this instance, the time zone will be determined by testing all time zones
       which have the given offset (and abbreviation if it is included) until one is found which
       matches both pieces of information. For more information about how this testing is done,
       refer to the def_zone method of the Date::Manip::TZ documentation.

VALID DATE FORMATS

       There are several categories of date formats supported by Date::Manip.  These are strings
       which specify only the year/month/day fields.

       These formats explicitly set the date, but not the time. These formats may be combined
       with a time string (as specified below) to set both the date and time. If this is not
       done, the default time is determined by the DefaultTime config variable.

       ISO 8601 dates
           The preferred date formats are those specified by ISO 8601. The specification includes
           valid calendar date and valid time formats.  Date::Manip will handle all of these
           formats, but does not require that the dates rigidly adhere to the specification since
           the ultimate goal of Date::Manip is to handle dates as they are represented in real
           life and some common variations exist which are similar to, but not identical to,
           those from the specification.

           A calendar date includes the following fields:

              CC    2-digit representation of the century
              YY    2-digit representation of the year in
                    a century
              MM    2-digit representation of a month
              DD    2-ditit representation of a day of month
              DoY   3-digit representation of a day of year
                    (001-366)
              Www   the character "W" followed by a 2-digit
                    week of the year (01-53)
              D     the day of the week (1-7)

           The following date formats are considered complete by Date::Manip. In the following,
           the date Thu Mar 5 2009 is used as an example.  This is the 64th day of the year. Thu
           is the 4th day of the week.  The week starting Mon, Mar 2 is the 10th week of the year
           (according the the ISO 8601 definition). Obviously, some of the formats are only valid
           when used at some times. For example, the format --MMDD refers to a month and day in
           the current year, so the date Mar 5, 2009 can only be specified using this format
           during 2009.

              Format      Notes   Examples

              CCYYMMDD            20090305
              CCYY-MM-DD          2009-03-05

              YYMMDD      1,2,4   090305
              YY-MM-DD            09-03-05

              -YYMMDD     3,4     -090305
              -YY-MM-DD           -09-03-05

              --MMDD      1       --0305
              --MM-DD             --03-05

              ---DD       1       ---05

              CCYYDoY             2009064
              CCYY-DoY            2009-064

              YYDoY       1,4     09064
              YY-DoY              09-064

              -YYDoY      3,4     -09064
              -YY-DoY             -09-064

              -DoY        1       -064

              CCYYWwwD            2009W104
              CCYY-Www-D          2009-W10-4

              YYWwwD      1,4     09W104
              YY-Www-D            09-W10-4

              -YYWwwD     3,4     -09W104
              -YY-Www-D           -09-W10-4

              -YWwwD      1       -9W104
              -Y-Www-D            -9-W10-4
                                  Y is the year (0-9) in
                                  current decade

              -WwwD       1       -W104
              -Www-D              -W10-4

              -W-D        1       -W-4
                                  D is day (1-7) in
                                  current week

              ---D        1       ---4
                                  same as -W-D

           The following date formats are truncated:

              CCYY-MM     2       2009-03

              CCYY                2009

              CC          2       20

              -YYMM       4       -0903
              -YY-MM              -09-03

              -YY         4       -09

              --MM                --03

              CCYYWww             2009W10
              CCYY-Www            2009-W10

              YYWww       4       09W10
              YY-Www              09-W10

              -YYWww      3,4     -09W10
              -YY-Www             -09-W10

              -Www                -W10

           Notes:

           1  These formats are considered truncated in the standard, but since
              they do include (or imply, using the current date for defaults) all of
              the fields, and since they do not introduce any parsing complexities,
              the standard is relaxed, and they are treated as complete.

           2  These formats are treated differently than in Date::Manip 5.xx as
              described below.

           3  These formats are not defined in the ISO 8601 spec, but
              are added for the sake of completeness since they do not
              add any parsing incompatibilities.

           4  Formats where the century is not given are described as a year in
              the current century in the specification. Date::Manip treats this
              more generically using the YYtoYYYY config variable. This will be
              used to determine how to determine the full year.

           Date::Manip 5.xx handled ISO 8601 dates in a less rigid fashion, and deviated from the
           specification in several formats. As of 6.00, the specification is followed much more
           closely so that all of the date formats included in it should produce valid dates.
           This changes, in a backwards incompatible way, the way a few strings will be
           interpreted as dates.

           As of 6.00, a two-digit date will be treated as CC. Previously, it was treated as YY.

           A six-digit date will be treated as YYMMDD. Previously, it was treated as YYYYMM.

           Previously, dashes were treated as optional in many cases. According to the
           specification, dates may be written in expanded form (with all dashes present) or
           abbreviate form (with no dashes). As of 6.00, this is the behavior, so the formats:
           YYMMDD and YY-MM-DD are allowed, as per the specification, but the format YY-MMDD is
           NOT allowed (though it was previously).

           The Www-D formats require a bit of explanation.  According to the specification, the
           date:

              1996-w02-3

           refers to the day with an ordinal number of 3 within the calendar week in the 2nd week
           of 1996.

           In the specification, the days of the week are numbered from 1 to 7 (Monday to
           Sunday), and the week always begins on Monday, so day 1 (Monday) is always the first
           day of the week, day 2 (Tuesday) is always the second day of the week, etc.

           In Date::Manip, the constraint that the week must start with Monday is relaxed,
           allowing the week to begin with Sunday (a far more common start of the week in
           calendars, at least in some parts of the world).

           This presents a problem though in that the above date could be interpreted as
           Wednesday (day 3) of the 2nd week of 1996, or as the 3rd day of the 2nd week of 1996
           (which would normally be Wednesday, but would be Tuesday if the week begins on
           Sunday).

           As of Date::Manip 6.00, the above date will be interpreted as the 3rd day of the 2nd
           week. This is a reversal from Date::Manip 5.xx, but I believe is what the
           specification would require. For more information, refer to the Date::Manip::Changes
           document.

       Common date formats
           Date::Manip supports a number of common date formats. The following fields may be
           included in a date:

             YY    2-digit representation of the year
             YYYY  4-digit representation of the year
             M     1- or 2- digit representation of the month
             MM    2-digit representation of the month
             D     1- or 2- digit representation of the day
             DD    2-digit representation of the day
             mmm   The abbreviated or full month name (i.e. Jan)

           The following date formats are supported:

              Format      Notes   Examples

              M/D         1,2     3/5
              M/D/YY      1       3/5/09
              M/D/YYYY    1       3/5/2009

              YYYY/M/D            2009/3/5

              mmm/D               Mar/5
              mmm/D/YY            Mar/5/09
              mmm/D/YYYY          Mar/5/2009
              D/mmm               5/Mar
              D/mmm/YY            5/Mar/09
              D/mmm/YYYY          5/Mar/2009
              YYYY/mmm/D          2009/Mar/5

              mmmD                Mar5
              mmmDDYY             Mar0509
              mmmDDYYYY           Mar052009
              Dmmm                5Mar
              DmmmYY              5Mar09
              DmmmYYYY            5Mar2009
              YYYYmmmD            2009Mar5

              mmmD YY             Mar5 09
              mmmD YYYY           Mar5 2009
              Dmmm YY             5Mar 09
              Dmmm YYYY           5Mar 2009

              mmm/D YY            Mar/5 09
              mmm/D YYYY          Mar/5 2009
              D/mmm YY            5/Mar 09
              D/mmm YYYY          5/Mar 2009

              YY   mmmD           09   Mar5
              YYYY mmmD           2009 Mar5
              YY   Dmmm           09   5Mar
              YYYY Dmmm           2009 5Mar

              YY   mmm/D          09   Mar/5
              YYYY mmm/D          2009 Mar/5
              YY   D/mmm          09   5/Mar
              YYYY D/mmm          2009 5/Mar

              YYYY:MM:DD          2010:01:15 (EXIF format)

           In the formats above, the slash (/) can be replace by any of the valid separators:
           whitespace, slash (/), period (.), or dash (-). The dash, though allowed, is
           discouraged since it may conflict with an ISO 8601 format.  For example, the format
           MM/DD/YY is just fine, but MM-DD-YY does not work since it conflicts with YY-MM-DD.
           To be safe, if "-" is used as a separator in a non-ISO format, they should be turned
           into "/" before calling the Date::Manip routines.

           No matter what separator is used, the same separator must be used throughout the date.
           For example, MM/DD/YY is valid and MM.DD.YY is also valid, but MM/DD.YY is NOT valid.

           Notes:

           1  With these formats, Americans tend to write month first, but many
              other countries tend to write day first.  The latter behavior can be
              obtained by setting the config variable DateFormat to something other
              than "US".

           2  The dot (.) separator may not be used in the M/D format since it
              will be interpreted as the H12,H+ format described below.

           These formats explicitly set the date, but not the time. The default time is
           determined by the DefaultTime config variable.

       Less common date formats
           The following formats are also supported by Date::Manip:

              DoW
                   The day of week of the current week
                      Friday
                      Friday at 12:40

              MMM Nth [YYYY]
              Nth MMM [YYYY]
              YYYY MMM Nth
              YYYY Nth MMM
                   Dec 1st 1970
                   1st Dec 1970
                   1970 Dec 1st
                   1970 1st Dec

              next/prev DoW
                   The next or last occurence of DoW
                      next Friday
                      last Friday at 12:40

              next/last week/month/year
                   The day one week/month/year from now
                   or in the past
                      next week
                      last month at 15:00

              last day in MMM [YYYY]
                   The last day of the month
                      last day in October
                      last day in October 1996

              last DoW in MMM [YYYY]
                   The last DoW in the month
                      last Tuesday in October
                      last Tuesday in October 1996

              last DoW in YYYY
                   The last DoW in the year
                      last Tuesday in 1997

                      NOTE: "last DoW" doesn't work in
                      English since the word "last"
                      is used for both this expression
                      and for "prev DoW", which gets
                      parsed first. "last DoW" MAY
                      work in other languages.

              Nth DoW in MMM [YYYY]
                   The Nth DoW in the month
                      3rd Tuesday in October
                      3rd Tuesday in October 1996

              Nth DoW [YYYY]
                   The Nth DoW in the year
                      22nd Sunday
                      22nd Sunday in 1996

              Nth day in MMM [YYYY]
                   The Nth day of the month
                      1st day of February
                      1st day of February 2012

              DoW week
                   British: same as "in 1 week on DoW"
                      Monday week

              DoW week N [YYYY]
              Dow Nth week [YYYY]
                   Sunday week 22
                   Sunday 22nd week
                      These refer to the day of week
                      of the Nth week of the year.

              Nth
                   12th
                      This refers to the Nth day of the
                      current month.

           Note that the formats "Sunday week 22" and "22nd Sunday" give different behaviors.
           "Sunday week 22" returns the Sunday of the 22nd week of the year based on how week 1
           is defined.  ISO 8601 defines week one to contain Jan 4, so "Sunday week 1" might be
           the first or second Sunday of the current year, or the last Sunday of the previous
           year.  "22nd Sunday" gives the actual 22nd time Sunday occurs in a given year,
           regardless of the definition of a week.

       Special date strings
           Most languages have strings which can be used to specify the date (relative to today).
           In English, these include the strings:

              today
              tomorrow
              yesterday

           There is also support for the British formats:

              today week
              tomorrow week
              yesterday week

           which refer to one week after today/tomorrow/yesterday respectively.

           Other languages have similar strings.

       Holidays
           You can parse holiday names as dates.  For example:

              Christmas
              Christmas 2010
              Christmas 2010 at noon
              Saturday Christmas 2010 at noon

       In all of the formats (except for ISO 8601 formats), the day of week ("Friday") can be
       entered anywhere in the date and it will be checked for accuracy.  In other words,

         "Tue Jul 16 1996 13:17:00"

       will work but

         "Jul 16 1996 Wednesday 13:17:00"

       will not (because Jul 16, 1996 is Tuesday, not Wednesday).

VALID TIME FORMATS

       There are several categories of time formats supported by Date::Manip.  These are strings
       which specify only the hour/minute/second fields.

       ISO 8601 times
           A time may be also be complete or truncated.  Again, Date::Manip treats some formats
           as complete even though the specification calls them truncated.

           A time may include the following fields:

              HH    2-digit representation of the hour
              MN    2-digit representation of the minutes
              SS    2-digit representation of the seconds
              H+    1+ digit representation of fractional hours
              M+    1+ digit representation of fractional minutes
              S+    1+ digit representation of fractional seconds

           The following time formats are considered complete by Date::Manip. The time 12:30:15
           will be expressed in the examples.

              Format      Notes   Examples

              HHMNSS      2       123015

              HH:MN:SS            12:30:15

              HHMNSS,S+           123015,5
              HH:MN:SS,S+         12:30:15,5
                                  Fractional seconds are ignored

              HHMN,M+             1230,25
              HH:MN,M+            12:30,25
                                  This is 12:30:00 + 0.25 minutes

              HH,H+               12,5
                                  This is 12:00:00 + 0.5 hours, so
                                  this is equivalent to 12:30:00

              -MNSS       1       -3015
              -MN:SS              -30:15

              --SS        1       --15

              -MNSS,S+    1       -3015,5
              -MN:SS,S+           -30:15,5

              -MN,M+      1       -30,25

              --SS,S+     1       --15,5

              HHMN        3       1230
              HH:MN               12:30

           The following time formats are truncated:

              HH                  12

              -MN                 -30

           Notes:

           1  These formats are considered truncated in the standard, but since
              they do include (or imply, using the current time for defaults) all of
              the fields, and since they do not introduce any parsing complexities,
              the standard is relaxed, and they are treated as complete.

           2  The HHMNSS format will not be correctly parsed since it is impossible
              to distinguish between it and YYMMDD. In order to parse an all-digit
              time, add the string ",0" to the end to force it to be interpreted
              as a time or include time zone information (either a zone name or
              abbreviation... an offset will not work in this case).

           3  The HH:MN format will be treated as complete, even though it is
              incomplete due to missing the seconds. In real life, expressing
              a time in the HH:MN format is very common, and is regarded as complete,
              and might include time zone information.

           ISO 8601 times may be followed by a time zone.  Date::Manip relaxes the constraints
           placed on the time zone format and allows any of the methods used to specify the time
           zone including time zone name, abbreviation, or offset. The time zone may be separated
           from the time by a space, but it is not required.

           Another constraint that is relaxed is that the fractional part may be specified using
           a period. In other words, the following are equivalent:

              12:30,25
              12:30.25

           It should be noted (as it is in the specification) that using a negative time zone
           offset may cause confusion. In addition to visually confusing, it may not be parsed
           correctly. For example, the time:

              123005-0300

           may not be parsed correctly. When using an offset time zone, you should always use the
           colon separators in the time:

              12:30:05-0300

       Other time formats
           A time may include any of the following fields:

              H24   1- or 2-digit representation of the hour (0-23)
              H12   1- or 2-digit representation of the hour (1-12)
              MN    2-digit representation of the minutes
              SS    2-digit representation of the seconds
              H+    1+ digit representation of fractional hours
              M+    1+ digit representation of fractional minutes
              S+    1+ digit representation of fractional seconds
              AM    A language specific AM/PM string

           The following time formats are accepted:

              Format              Examples

              H24:MN:SS           17:30:15
              H12:MN:SS AM        5:30:15 PM
              H12:MN:SS

              H24:MN:SS,S+        17:30:15,5
              H12:MN:SS,S+ AM     5:30:15,5 PM
              H12:MN:SS,S+        Fractional seconds are ignored

              H24:MN,M+           17:30,25
              H12:MN,M+ AM        5:30,25 PM
              H12:MN,M+           This is 17:30:00 + 0.25 minutes

              H24,H+              17,5
              H12,H+ AM           5,5 PM
              H12,H+              This is 17:00:00 + 0.5 hours, so
                                  this is equivalent to 17:30:00

              H24:MN              17:30
              H12:MN AM           5:30 PM
              H12:MN

              H12 AM              5 PM

           The fractional part may be specified using a comma, a period, or a colon. A language
           specific fractional separator may also be available for some languages. A colon will
           only work if the hour, minute, and second are all explicitly included, but will not
           work otherwise.

           In other words, the following are equivalent:

              12:30:20,25
              12:30:20.25
              12:30:20:25

           Some languages have alternate H:MN and MN:S separators. For example, one H:MN
           separator in French is 'h' (the MN:S separator is still a colon), so the following are
           equivalent:

              12:30:00
              12h30:00

           Time zone information can be included immediately following the time.  It can be
           separated by whitespace from the time, or it can be immediately adjacent.

       Special time strings
           Different languages may have some words which can be used to specify a certain time of
           day. In English, for example, the following words are equivalent to the time listed:

              noon        12:00:00
              midnight    00:00:00

           So, the following are equivalent:

              Jan 2 2009 at noon
              Jan 2 2009 12:00:00

           There were two possible ways to interpret midnight. One was at the start of the day
           (00:00:00) and the other was at the end of the day (24:00:00 which would actually mean
           at 00:00:00 of the following day).  The first has been used to maintain backwards
           compatibility with Date::Manip 5.xx .

           Other languages have similar strings.

       In most languages, a word similar to "at" may precede the time (this does NOT apply to ISO
       8601 time formats). This word (which must be separate from all other parts of the date
       with whitespace) is optional, and the following are equivalent:

          12:30
          at 12:30

       The times "12:00 am", "12:00 pm", and "midnight" are not well defined.  Date::Manip uses
       the following convention:

         midnight = 12:00am = 00:00:00
         noon     = 12:00pm = 12:00:00

       and the day goes from 00:00:00 to 23:59:59.  In other words, midnight is the beginning of
       a day rather than the end of one.  The time 24:00:00 is also allowed (though it is
       automatically transformed to 00:00:00 of the following day). This gives the unusual result
       of parsing:

         Wed Feb 8 2006 24:00:00

       which gives the date of:

         Thu Feb 9 2006 00:00:00

VALID COMBINED DATE AND TIME FORMATS

       There are several categories of strings which specify both the date and time. These
       include the following:

       ISO 8601 combined date and time
           A combined ISO 8601 date and time is a string containing a complete ISO 8601 date and
           a complete or truncated ISO 8601 time.

           Date::Manip relaxes the restrictions on how the two are combined.  The time may be
           separated from the date by space, dash, or the letter T, or the two may be joined with
           nothing separating them.

           When the time immediately follows the date, or when the two are separated by a dash,
           the resulting string MUST be unambiguous. Provided the date includes all of the dashes
           in it (i.e. YY-MM-DD instead of YYMMDD), it is rare that there is any ambiguity. If
           the date does not include dashes, the strings may be ambiguous, and in this case,
           separating the date and time with a space or the letter T is useful (and perhaps
           necessary) to correctly interpret the string.

           The DoY formats should always be separated from the time by something. They are
           visually confusing if they are not separated from the time.

           Time zone information can be included immediately following a complete time.  It may
           not be included if no time is given, or if a truncated time is included. The time zone
           may be separated from the time with whitespace, or it can be immediately adjacent to
           it (since the ISO 8601 specification allows it in some cases).

       Non-ISO 8601 combined date and time
           A date from any of the formats above (except for the ISO 8601 formats) may be combined
           with any of the time formats above (except for the ISO 8601 time formats) in any
           combination to form a valid combined date and time.

       Deltas
           Dates are often specified in terms of a delta from "now". For example, "in 2 days".

           Any valid delta can be used to specify a date, and the date is defined as that delta
           added to "now". Refer to the Date::Manip::Delta documentation for a list of valid
           delta formats.

           If the delta itself does not include a time part, the time may be specified
           explicitly. For example:

              in 3 days at 12:00:00

           will take the delta part "in 3 days" and add it to the current time, then set the time
           to 12:00:00.

           It is NOT allowed to include an explicit time if any time segment was included in the
           delta. For example, the following is invalid:

              in 3 days 2 hours at 12:00:00

           One additional format that is supported is to include only week (or higher) components
           in the delta and to set the day of week. For example:

             Friday in 2 weeks
             in 2 weeks on Friday
             Friday 2 weeks ago
             2 weeks ago on Friday at 13:45

           These first apply the delta (of weeks, months, and years) to the current time, and
           then set the day to the given day-of-week in that week.

       Special date and time strings
           Most language have strings which can be used to specify the full date and time
           (relative to the current date and time). In English, these include the string:

              now

       Addition combined date and time formats
           The following formats are also supported:

              epoch SECS
                 The number of seconds since the epoch
                 (Jan 1, 1970 00:00:00 GMT). SECS may
                 be negative to give time before the
                 epoch.

       A couple of notes:

       Commas may be included in all date formats arbitrarily (except for ISO 8601 formats where
       they may only be included when allowed by the specification).

       The time/time zone is removed from the date before the date is parsed, so the time may
       appear before or after the date, or between any two parts of the date.

       The time and the zone do not need to be adjacent, so the string:

          Jan 21 17:13:27 2010 -0400

       will work.  If the timezone is separate from the date, it MUST be separated from any other
       portion of the date by whitespace.

       Certain words such as "on", "in", "at", "of", etc. which commonly appear in a date or time
       are ignored (except in ISO 8601 formats).

PRINTF DIRECTIVES

       The following printf directives are replaced with information from the date.

          Year
              %y     year                     - 00 to 99
              %Y     year                     - 0001 to 9999

          Month, Week
              %m     month of year            - 01 to 12
              %f     month of year            - " 1" to "12"
              %b,%h  month abbreviation       - Jan to Dec
              %B     month name               - January to December

          Day
              %j     day of the year          - 001 to 366
              %d     day of month             - 01 to 31
              %e     day of month             - " 1" to "31"
              %v     weekday abbreviation     - " S"," M"," T", ...
              %a     weekday abbreviation     - Sun to Sat
              %A     weekday name             - Sunday to Saturday
              %w     day of week              - 1 to 7 (1=Monday)
              %E     day of month with
                     suffix                   - 1st, 2nd, 3rd...

          Hour
              %H     hour                     - 00 to 23
              %k     hour                     - " 0" to "23"
              %i     hour                     - " 1" to "12"
              %I     hour                     - 01 to 12
              %p     AM or PM

          Minute, Second, Time zone
              %M     minute                   - 00 to 59
              %S     second                   - 00 to 59
              %Z     time zone abbreviation   - EDT
              %z     time zone as GMT offset  - +0100 (see Note 4)
              %N     time zone as GMT offset  - +01:00:00

          Epoch (see NOTE 3 below)
              %s     seconds from
                     1/1/1970 GMT             - negative if before
              %o     seconds from 1/1/1970
                     in the current time
                     zone

          Date, Time
              %c     %a %b %e %H:%M:%S %Y     - Fri Apr 28 17:23:15 1995
              %C,%u  %a %b %e %H:%M:%S %Z %Y  - Fri Apr 28 17:25:57 EDT 1995
              %g     %a, %d %b %Y %H:%M:%S %Z - Fri, 28 Apr 1995 17:23:15 EDT
              %D     %m/%d/%y                 - 04/28/95
              %x     %m/%d/%y or %d/%m/%y     - 04/28/95 or 28/04/28
                                                (Depends on DateFormat variable)
              %l     date in ls(1) format (see NOTE 1 below)
                       %b %e %H:%M            - Apr 28 17:23 (*)
                       %b %e  %Y              - Apr 28  1993 (*)
              %r     %I:%M:%S %p              - 05:39:55 PM
              %R     %H:%M                    - 17:40
              %T,%X  %H:%M:%S                 - 17:40:58
              %V     %m%d%H%M%y               - 0428174095
              %Q     %Y%m%d                   - 19961025
              %q     %Y%m%d%H%M%S             - 19961025174058
              %P     %Y%m%d%H:%M:%S           - 1996102517:40:58
              %O     %Y-%m-%dT%H:%M:%S        - 1996-10-25T17:40:58
              %F     %A, %B %e, %Y            - Sunday, January  1, 1996
              %K     %Y-%j                    - 1997-045

          Special Year/Week formats (see NOTE 2 below)
              %G     year, Monday as first
                     day of week              - 0001 to 9999
              %W     week of year, Monday
                     as first day of week     - 01 to 53
              %L     year, Sunday as first
                     day of week              - 0001 to 9999
              %U     week of year, Sunday
                     as first day of week     - 01 to 53
              %J     %G-W%W-%w                - 1997-W02-2

          Other formats
              %n     insert a newline character
              %t     insert a tab character
              %%     insert a `%' character
              %+     insert a `+' character

          All other characters are currently unused, but may be used in the
          future.  They currently insert the character following the %.

          The following multi-character formats also exist:

          Extended formats
              %<A=NUM>   These returns the NUMth value of the %A, %a, and %v formats
              %<a=NUM>   resepectively.  In English, that would yield:
              %<v=NUM>      %<A=2>   => Tuesday
                            %<a=2>   => Tue
                            %<v=2>   => T
                         NUM must be in the range 1-7.

              %<B=NUM>   These return the NUMth value of the %B and %b formats
              %<b=NUM>   respectively.  In English, that would yield:
                            %<B=2>   => February
                            %<b=2>   => Feb
                         NUM must be in the range 1-12 (or 01-12).

              %<p=NUM>   These return the NUMth value of the %p format.  In
                         English, that would yield:
                            %<p=1>   => AM
                            %<p=2>   => PM
                         NUM must be in the range 1-2.

              %<E=NUM>   These return the NUMth value of the %E format.  In
                         English, that would yield:
                            %<E=1>   => 1st
                            %<E=53>  => 53rd
                         NUM must be in the range 1-53.

       If a lone percent is the final character in a format, it is ignored.

       The formats used in this routine were originally based on date.pl (version 3.2) by Terry
       McGonigal, as well as a couple taken from different versions of the Solaris date(1)
       command.  Also, several have been added which are unique to Date::Manip.

       NOTE 1:

       The ls format (%l) applies to date within the past OR future 6 months!  Any date that is
       before the date NOW - 6 months, or that is on or after the date NOW + 6 months will have
       the year printed out.

       The later time must be on or after so that there is no ambiguity. If it is now
       2000-06-06-12:00:00, then the date 1999-12-06-12:00:00 will be written as "Dec 6 12:00"
       but the date 2000-12-06-12:00:00 will be written as "Dec 6 2000".

       NOTE 2:

       The %U, %W, %L, %G, and %J formats are used to support the ISO-8601 format: YYYY-wWW-D.
       In this format, a date is written as a year, the week of the year, and the day of the
       week.  Technically, the week may be considered to start on any day of the week, but Sunday
       and Monday are the both common choices, so both are supported.

       The %W and %G formats return the week-of-year and the year treating weeks as starting on
       Monday.

       The %U and %L formats return the week-of-year and the year treating weeks as starting on
       Sunday.

       Most of the time, the %L and %G formats returns the same value as the %Y format, but there
       is a problem with days occurring in the first or last week of the year.

       The ISO-8601 representation of Jan 1, 1993 written in the YYYY-wWW-D format is actually
       1992-W53-5.  In other words, Jan 1 is treated as being in the last week of the preceding
       year.  Depending on the year, days in the first week of a year may belong to the previous
       year, and days in the final week of a year may belong to the next year.  The week is
       assigned to the year which has most of the days.  For example, if the week starts on
       Sunday, then the last week of 2003 is 2003-12-28 to 2004-01-03.  This week is assigned to
       2003 since 4 of the days in it are in 2003 and only 3 of them are in 2004.  The first week
       of 2004 starts on 2004-01-04.

       The %U and %W formats return a week-of-year number from 01 to 53. %L and %G return the
       corresponding year, and to get this type of information, you should always use the (%W,%G)
       combination or (%U,%L) combination. %Y should not be used as it will yield incorrect
       results.

       %J returns the full ISO-8601 format (%G-W%W-%w).

       NOTE 3:

       The %s and %o formats return negative values if the date is before the start of the epoch.
       Other Unix utilities would return an error, or a zero, so if you are going to use
       Date::Manip in conjunction with these, be sure to check for a negative value.

       NOTE 4:

       The %z format returns the offset in the RFC 822 specified format +0500 .  Most offsets are
       full hour amounts, so this is not a problem, but some offsets are irregular (+05:17:30).
       In this case, the string returned is +051730 which isn't RFC 822 compliant, but since RFC
       822 ignores this situation, I had to decide between returning an incorrect value, or
       breaking strict compliance, and I chose the second option.

KNOWN BUGS

       None known.

BUGS AND QUESTIONS

       Please refer to the Date::Manip::Problems documentation for information on submitting bug
       reports or questions to the author.

SEE ALSO

       Date::Manip        - main module documentation

LICENSE

       This script is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

AUTHOR

       Sullivan Beck (sbeck@cpan.org)