Recurring schedules

Package: FINANCE_PACKAGE. Registered by createEngine(); for a slimmer engine, register it explicitly (see choosing packages).

A payment that repeats, a subscription, a salary, an instalment plan, adds up to a total over the time it runs. <amount> <period> for <duration> works that total out in place, so the sum does not have to be calculated elsewhere and typed back in.

450 monthly for 18 months // 8,100
12.99 monthly for 2 years // 311.76
2000 every 2 weeks for 6 months // 26,000

The period is daily, weekly, monthly, yearly (also annually), or every N days/weeks/months/years. Money rides along and, where the amount is exact, so is the total.

$12.99 monthly for 2 years // $311.76

The total is the result. The number of payments is how it is reached, one per whole period on a scheduling year where a month is one of twelve and a week one of fifty-two, so every 2 weeks for 6 months is thirteen payments over half a year. A final part-period has not come due, so it is not counted.

2000 every 2 weeks for 5 weeks // 4,000