Time-Keeper-Recurrence Rules that say when something happens again: RFC 5545 recurrence rules, cron expressions in Punk::Queue's grammar, and named arguments such as every(2, 'weeks', on => [qw(tue thu)]), walked in any time zone and in any calendar Time::Keeper has (RFC 7529). A rule with dates added and removed, or several rules, is a set; sets are read and written as iCalendar text; rules and sets are stored as text with their zone by name. A C ABI lets a scheduler written in C compile a rule and walk it, or ask for a cron's next occurrence in one call. INSTALLATION Time::Keeper::Zone and Time::Keeper must be installed first: this builds against their headers. perl Makefile.PL make make test make install LICENSE AND COPYRIGHT This software is Copyright (c) 2026 by LNATION. This is free software, licensed under: The Artistic License 2.0 (GPL Compatible)