What is the type of an empty return from match()?

In the following:
julia> e = if false; end

julia> e

julia> f = match(r"x", “y”)

julia> f

julia> a =
0-element Array{Any,1}

julia> e == a

julia> e == f

…What is the type of e and f which they are equal to?

You can just ask the help system:

julia> f = match(r"x", "y")

help?> f
search: fd for fma fld fft full fld1 find filt fill fft! fdio

  No documentation found.

  f is of type Void.


  struct Void <: Any

help?> Void
search: Void @vectorize_2arg @vectorize_1arg versioninfo


  A type with no fields that is the type nothing.

help?> nothing
search: nothing


  The singleton instance of type Void, used by convention
  when there is no value to return (as in a C void
  function). Can be converted to an empty Nullable value.

or just typeof if you just want to know the type.