First in Swift

first.swift

/**
    Find the first element in a sequence passing a test.

    :param: source Source sequence to iterate
    :param: includeElement Closure to evaluate elements with
    :return: First element in the sequence for which includeElement returns true, or nil if none found
*/
public func first<S: SequenceType>(source: S, includeElement: (S.Generator.Element) -> Bool) -> S.Generator.Element? {
    var filteredSource = lazy(source).filter(includeElement).generate()
    return filteredSource.next()
}