Query: set::infinite::_recurrence
OS: debian
Section: 3pm
Format: Original Unix Latex Style Formatted with HTML and a Horizontal Scroll Bar
Set::Infinite::_recurrence(3pm) User Contributed Perl Documentation Set::Infinite::_recurrence(3pm)NAMESet::Infinite::_recurrence - Extends Set::Infinite with recurrence functionsSYNOPSIS$recurrence = $base_set->_recurrence ( &next, &previous );DESCRIPTIONThis 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.METHODSo _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 ), " "; # 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 ), " "; # 235 print "previous occurence before $x = ", $recurrence->{param}[2]->( $x ), " "; # 234 } { my $x = 234; print "next occurence after $x = ", $recurrence->{param}[0]->( $x ), " "; # 235 print "previous occurence before $x = ", $recurrence->{param}[2]->( $x ), " "; # 233 } o is_forever Returns true if the set is a single span, ranging from -Infinity to Infinity. o _is_recurrence Returns true if the set is an unbounded recurrence, ranging from -Infinity to Infinity.CONSTANTSo INFINITY The "Infinity" value. o NEG_INFINITY The "-Infinity" value.SUPPORTSupport is offered through the "datetime@perl.org" mailing list. Please report bugs using rt.cpan.orgAUTHORFlavio Soibelmann Glock <fglock@gmail.com> The recurrence generation algorithm is based on an idea from Dave Rolsky.COPYRIGHTCopyright (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 ALSOSet::Infinite DateTime::Set For details on the Perl DateTime Suite project please see <http://datetime.perl.org>. perl v5.12.4 2011-08-22 Set::Infinite::_recurrence(3pm)