# Checks if all elements respect a predicate
        #
        # ~~~~nitish
        # fun lt10(x: Int): Bool do return x < 10
        #
        # var pred = &lt10
        # var xs = [1..9]
        # assert xs.iterator.all(pred)
        # assert [].iterator.all(pred)
        # assert not [1..10].iterator.all(pred)
        # ~~~~
        fun all(pred: Fun1[E,Bool]): Bool
        do
                for x in self do
                        if not pred.call(x) then
                                return false
                        end
                end
                return true
        end