There are lots of domain-specific languages for schedules. The most prominent might be Cron (for *nix scheduled tasks),but there's also RRULE (for iCalendar events) and many others. Cron isn't precisely what I'd call human-friendly. Can you order me what 10 8,20 * 8 1-5 means if you don't use Cron often? Some DSLs recede in the opposite direction and are wildly verbose, or will sacrifice expressiveness for simplicity.
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