So I'm looking at base/set.jl, and I'm almost immediately puzzled by some syntax.
union!(s::Set, xs) = (for x=xs; push!(s,x); end; s) What is xs? I might have expected union!(s::Set, xs...) = (for x in xs; push!(s,x); end; s) but "for x=xs" I don't get. Can someone explain how this syntax works?
