gistfile1.rb

def to_lambda &block
  obj = Object.new
  obj.define_singleton_method(:_, &block)
  return obj.method(:_).to_proc
end

def with_file(name, &block)
  l = to_lambda(&block)
  puts "Open file"
  f = File.open(name, "r")
  l[f]
  puts "Close file"
  f.close
end


content = ""
with_file("/etc/hosts") do |f|
  puts "Read content"
  return 'hho'
  content << f.read
end
p content