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Set::Infinite::_recurrence.3pm
Langue: en
Version: 2009-02-26 (fedora - 05/07/09)
Section: 3 (Bibliothèques de fonctions)
NAME
Set::Infinite::_recurrence - Extends Set::Infinite with recurrence functionsSYNOPSIS
$recurrence = $base_set->_recurrence ( \&next, \&previous );
DESCRIPTION
This is an internal class used by the DateTime::Set module. The API is subject to change.It provides all functionality provided by Set::Infinite, plus the ability to define recurrences with arbitrary objects, such as dates.
METHODS
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- _recurrence ( \&next, \&previous )
Creates a recurrence set. The set is defined inside a 'base set'.
$recurrence = $base_set->_recurrence ( \&next, \&previous );
The recurrence functions take one argument, and return the 'next' or the 'previous' occurence.
Example: defines the set of all 'integer numbers':
use strict; use Set::Infinite::_recurrence; use POSIX qw(floor); # define the recurrence span my $forever = Set::Infinite::_recurrence->new( Set::Infinite::_recurrence::NEG_INFINITY, Set::Infinite::_recurrence::INFINITY ); my $recurrence = $forever->_recurrence( sub { # next floor( $_[0] + 1 ) }, sub { # previous my $tmp = floor( $_[0] ); $tmp < $_[0] ? $tmp : $_[0] - 1 }, ); print "sample recurrence ", $recurrence->intersection( -5, 5 ), "\n"; # sample recurrence -5,-4,-3,-2,-1,0,1,2,3,4,5 { my $x = 234.567; print "next occurence after $x = ", $recurrence->{param}[0]->( $x ), "\n"; # 235 print "previous occurence before $x = ", $recurrence->{param}[2]->( $x ), "\n"; # 234 } { my $x = 234; print "next occurence after $x = ", $recurrence->{param}[0]->( $x ), "\n"; # 235 print "previous occurence before $x = ", $recurrence->{param}[2]->( $x ), "\n"; # 233 }
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- is_forever
Returns true if the set is a single span, ranging from -Infinity to Infinity.
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- _is_recurrence
Returns true if the set is an unbounded recurrence, ranging from -Infinity to Infinity.
CONSTANTS
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- INFINITY
The "Infinity" value.
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- NEG_INFINITY
The "-Infinity" value.
SUPPORT
Support is offered through the "datetime@perl.org" mailing list.Please report bugs using rt.cpan.org
AUTHOR
Flavio Soibelmann Glock <fglock@pucrs.br>The recurrence generation algorithm is based on an idea from Dave Rolsky.
COPYRIGHT
Copyright (c) 2003 Flavio Soibelmann Glock. All rights reserved. This program is free software; you can distribute it and/or modify it under the same terms as Perl itself.The full text of the license can be found in the LICENSE file included with this module.
SEE ALSO
Set::InfiniteDateTime::Set
For details on the Perl DateTime Suite project please see <http://datetime.perl.org>.
Contenus ©2006-2024 Benjamin Poulain
Design ©2006-2024 Maxime Vantorre