I'm not sure if I am misunderstanding your argument, but it seems like you're complaining about the fact you can't pass "functions" to methods that accept a block? You can! :D

    times_two = -> (x) {x*2}       # Proc (lambda)
    times_two = Proc.new {|x| x*2} # Proc
    [7, 13, 19, 23, 31].map(&times_two)

Also, if you want to call a method on the objects, you could do:

    [7, 13, 19, 23, 31].map(&:to_s)

Which is a bizarre syntax, if you ask me (actually, not really if you know how I works in the background, but it still does look bizarre IHMO).