draft intersect and union functions for Julia vectors

vect_set.jl

# to do set stuff with vectors, turn the B vector into a set, then 
# iterate over the a vector, creating a set to remove dupes.
# This is moderately efficient, preserves order, and removes dupes.
function intersect{T}(a::Vector{T}, b::Vector{T})
    bset = Set(b...)
	aset = Set()
	ret = T[]
	for a_elem in a 
		if has(bset, a_elem) && !has(aset, a_elem)
			push(ret, a_elem)
			add(aset, a_elem)
		end
	end
	ret
end
function union{T}(a::Vector{T}, b::Vector{T})
	ret = T[]
	seen = Set{T}()
	for a_elem in a
		if !has(seen, a_elem)
			push(ret, a_elem)
			add(seen, a_elem)
		end
	end
	for b_elem in b
		if !has(seen, b_elem)
			push(ret, b_elem)
			add(seen, b_elem)
		end
	end
	ret
end