I browsed through some Github issues where this was discussed, but I'm
unclear on the outcome. It's complicated.
Is the result of `map` on an empty array going to be typed correctly any
time soon? Ever? In 0.5, maybe? A comprehension seems to work now (this is
on 0.4.6, the generic Linux binary), while `map` still inherits the type
of the empty input array:
```julia
julia> cumsum(map(length, UTF8String[]))
ERROR: BoundsError: attempt to access 0-element Array{UTF8String,1}
at index [1]
in cumsum at arraymath.jl:450
julia> cumsum([length(s) for s in UTF8String[]])
0-element Array{Int64,1}
```
Some of my input arrays will be empty, so I need at least a temporary
workaround, but should I give up on `map` altogether, or be patient?
