Re: [rt.cpan.org #34912] Constants for months/weekdays?

2008/4/12, Flavio Poletti via RT <[email protected]>:
>  Sat Apr 12 08:41:24 2008: Request 34912 was acted upon.
>  Transaction: Ticket created by POLETTIX
>        Queue: DateTime
>      Subject: Constants for months/weekdays?
>    Broken in: 0.42
>     Severity: Wishlist
>        Owner: Nobody
>   Requestors: [email protected]
>       Status: new
>   Ticket <URL: http://rt.cpan.org/Ticket/Display.html?id=34912 >
>
>  Hi,
>
>    I think it would be useful to have some constants exported by the
>  module to refer to month names and weekdays, like JANUARY, JANUARY_0 and
>  so on. Otherwise, it's likely that the users will define such constants
>  by themselves (or worse hardcode them), leading to potential bugs.
>
>  I noticed this while reading http://use.perl.org/~Aristotle/journal/36022.


# Reference: http://use.perl.org/~Aristotle/journal/36022

{
#--------------
# implementation using the "ICal" module

use DateTime::Event::ICal;
print "with ICal\n";
my $first_thursday = DateTime::Event::ICal->recur(
    freq => 'monthly',
    byday => [ '1th' ]
);
my $fridays = DateTime::Event::ICal->recur(
    freq => 'weekly',
    byday => [ 'fr' ]
);
my $first_friday = DateTime::Event::ICal->recur(
    freq => 'monthly',
    byday => [ '1fr' ]
);
my $last_friday = DateTime::Event::ICal->recur(
    freq => 'monthly',
    byday => [ '-1fr' ]
);

my $dt = DateTime->today;
my $dt_month = DateTime->today->truncate( to => 'month' )->add( months => 1 );

print 'First Friday of this month: ',
   $first_friday->previous( $dt_month ), "\n";

print 'Last Friday of this month: ',
   $last_friday->previous( $dt_month ), "\n";

print 'The Friday before today: ',
   $fridays->previous( $dt ), "\n";

print 'London.pm heretics meeting this month: ',
   $first_thursday->previous( $dt_month ), "\n";

print "\n";
#--------------
}


{
#--------------
# implementation using the "Recurrence" module
# - requires a little more calculations; more error-prone

use DateTime::Event::Recurrence;
print "with Recurrence\n";
my $thursdays = DateTime::Event::Recurrence->weekly( days => [ 'th' ] );
my $fridays   = DateTime::Event::Recurrence->weekly( days => [ 'fr' ] );

my $dt = DateTime->today;

print 'First Friday of this month: ',
   $fridays->next( $dt->clone->truncate( to => 'month' )->subtract(
days => 1 ) ), "\n";

print 'Last Friday of this month: ',
   $fridays->previous( $dt->clone->truncate( to => 'month' )->add(
months => 1 ) ), "\n";

print 'The Friday before today: ',
   $fridays->previous( $dt ), "\n";

print 'London.pm heretics meeting this month: ',
   $thursdays->next( $dt->clone->truncate( to => 'month' )->subtract(
days => 1 ) ), "\n";

print "\n";
#--------------
}

# First Friday of this month: 2008-04-04T00:00:00
# Last Friday of this month: 2008-04-25T00:00:00
# The Friday before today: 2008-04-11T00:00:00
# London.pm heretics meeting this month: 2008-04-03T00:00:00