[julia-users] support for '?' suffix on functions that return boolean types.

[Aerlinger]

Ruby has a useful convention where methods can end in a '?' to indicate 
that it returns a boolean value. This capability would be useful in Julia 
as well. Much like the bang (!) suffix on functions it might look something 
like this:

function isEven?(n::Int)
  n % 2 == 2
end


isEven?(4)  # => true