Use a Ruby method like a block or lambda

Sometimes you want to use a vanilla Ruby method like a block. You can use Object#method Show archive.org snapshot to obtain a method reference that responds to #call:

foo_plus = "foo".method(:+)
foo_plus.call("bar") # => "foobar"

The method reference also understands #to_proc so you can feed it to block-taking methods by prefixing it with &:

printer = method(:puts)
[1, 2, 3].each(&printer) # will print one line per number