KvadrantDate

A date, as three numbers, because a picker is a control and not a calendar.

kotlinx-datetime was the obvious choice and is not made here. Its LocalDate is exactly this type and is the Kotlin multiplatform standard — but putting it on kvadrant-core's API puts it on every consumer of a Metro button, and a component library is not the right place to decide which date library an application uses. Three integers convert to whatever the caller already has in one line, and only at the one call site that opened a picker.

The arithmetic this costs is daysInMonth and it is five lines of the Gregorian rule.

Parameters