# Repetition of arrays.
	#
	# returns a new array built by concatenating `self` `repeat` times.
	#
	#     var a = [1,2,3]
	#     assert (a * 0).is_empty
	#     assert a * 1  ==  [1,2,3]
	#     assert a * 2  ==  [1,2,3,1,2,3]
	#     assert (a * 10).length  ==  30
	fun *(repeat: Int): Array[E]
	do
		assert repeat >= 0
		var res = new Array[E].with_capacity(length * repeat)
		while repeat > 0 do
			res.add_all(self)
			repeat -= 1
		end
		return res
	end