Blocks In-depth: Procs

ampersand.rb

def connect(address, &log)
  log.call("About to connect…")
  response = do_actual_connection(address)
  log.call("Error: #{response.message}") if response.error?
end

connect("http://localhost") { |msg| puts "Info: #{msg}" }

keep_proc.rb

def connect(address, log)
  log.call("About to connect…")
  response = do_actual_connection(address)
  log.call("Error: #{response.message}") if response.error?
end

my_proc = proc { |msg| puts "Info: #{msg}" }
connect("http://localhost", my_proc)

kernel_proc.rb

p = proc { |name| "Hello, #{name}!" }

p.("Omer") # huh?
p["Omer"] # oh my!
p === "Omer" # WTFZ

new_proc.rb

p = Proc.new { |name| "Hello, #{name}!" }
p.call("Omer") # => "Hello, Omer!"