How the matching works

// A couple must be opposite genders, in the same city, and within
// 8 years of age — and never a pair we've already introduced.
func compatible(a, b Person) bool {
    return a.Gender != b.Gender &&
        a.City == b.City &&
        abs(a.Age-b.Age) <= 8
}

// Every week, after Shabbat, for each person who reconfirmed we pick
// the closest-in-age partner they have never met before.
for _, a := range confirmedThisWeek {
    var best *Person
    for _, b := range confirmedThisWeek {
        if taken[b] || alreadyMatched(a, b) {
            continue
        }
        if compatible(a, b) && closerInAge(a, b, best) {
            best = b
        }
    }
    if best != nil {
        introduce(a, best) // one match, revealed at motzei Shabbat
    }
}