# func1 generates a sequence of items derived from x
# func2 does something with the items generated by func1
def test(x,func1,func2)
    func1.call(x) do | y |
        func2.call(y)
    end
end

func1 = lambda do | x |
    for i in 1 .. 5
        yield x * i
    end
end

func2 = lambda do | y |
    puts y
end


test(2,func2) # Should print '2','4','6','8',and '10'

当然,这不起作用.

test.rb:11: no block given (LocalJumpError)
    from test.rb:10:in `each'
    from test.rb:10
    from test.rb:4:in `call'
    from test.rb:4:in `test'
    from test.rb:20