function sprintfrange(a::Vector{T}) where T<:Integer
    isempty(a) && return ""
    len = length(a)
    dropme = falses(len)
    dropme[2:end-1] = Bool[a[i-1]==a[i]-1 && a[i+1]==a[i]+1 for i in 2:(len-1)]
    s = [dropme[i] ? "X" : string(a[i]) for i in 1:len]
    s = join(s, ",")
    replace(s, r",[,X]+," => "-")
end

testa = [ 0,  1,  2,  4,  6,  7,  8, 11, 12, 14,
         15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
         25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
         37, 38, 39]

println("Testing range-style formatting.")
println("   ", testa, "\n       =>\n   ", sprintfrange(testa))