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lib/App/Chart/Timebase.pm  view on Meta::CPAN

=item C<< App::Chart::Timebase::Years->new_from_iso ($start) >>

=item C<< App::Chart::Timebase::Decades->new_from_iso ($start) >>

Create and return a new timebase object representing the given
days/weeks/etc type of period, and with a 0 at the given C<$start> date.
C<$start> is an ISO format string like "2007-12-31".

Days means weekdays, ie. trading days.  Weeks is calendar weeks starting
from each Monday, through to the following Sunday.  Months is calendar
months.  Quarters are calendar quarters like Jan/Feb/Mar then Apr/May/Jun,
etc.

=item C<< $timebase->to_iso ($t) >>

Return an ISO date string like "2007-12-31" for the given C<$t> timebase
index (an integer).  For example,

    my $timebase = App::Chart::Timebase::Days->new_from_iso ('2008-05-01');
    my $iso = $timebase->to_iso (5);
    # $iso is '2008-05-08'  (weekday 5 counting from 0 at 1 May)

=item C<< $timebase->from_ymd_floor ($year, $month, $day) >>

=item C<< $timebase->from_iso_floor ($str) >>

=item C<< $timebase->from_iso_ceil ($str) >>

Return a time value (an integer) in C<$timebase> which corresponds to the
given date, either as values C<$year>, C<$month> and C<$day>, or an ISO date
string C<$str> like "2007-12-31".

If the date is not representable in C<$timebase>, then for C<floor> the
return is the next earlier timebase value or for C<ceil> the next later.
This only arises on a C<Days> timebase when the date requested is a Saturday
or Sunday.  In that case C<floor> gives the preceding Friday or C<ceil> the
following Monday.

=item C<< $timebase->convert_from_floor ($from_timebase, $from_t) >>

=item C<< $timebase->convert_from_ceil ($from_timebase, $from_t) >>

Convert an time value in C<$from_timebase> to a value in C<$timebase>.  The
two timebases can have different starting points and different units, such
as converting a day number into a week number.

When the destination C<$timebase> is a higher resolution than
C<$from_timebase> the C<convert_from_floor> version gives the start of the
C<$from_t> period and the C<convert_from_ceil> version gives the end.  For
example if C<$from_timebase> is years but the destination C<$timebase> is
months then C<floor> gives the first month (ie. January) in the C<$from_t>
year and C<ceil> gives the last month (ie. December).

=item $timebase->strftime ($format, $t)

Return an C<strftime> formatted string which is timebase value C<$t> (an
integer) under C<$format>.  For example,

    $timebase->strftime ('%d %b %Y', $t)
    # gives say "31 December 2007"

=item $timebase->today ()

=item $timebase->today ($timezone)

Return today's date as an integer in C<$timebase>.  The optional
C<$timezone> is a C<App::Chart::TZ> object to use, or the default is
local time.

=item C<< $timebase->adjective() >>

Return a string which is an adjective for the C<$timebase>.  For example on
a years timebase the return would be C<"Yearly">.  The string is translated
through the usual Chart internationalizations if possible.

=back

=cut