Understanding blocks in ruby

gistfile1.rb

# Normally a block is passed after the arguments
[1,2,3].map(){ |i| i.next }

# & passes the argument as a block
[1,2,3].map(&:next)

# & arguments are cast to a Proc
[1,2,3].map(&:next.to_proc)

# Procs are already procs
[1,2,3].map(&Proc.new { |i| i.next })

# But you can cast them too
[1,2,3].map(&Proc.new { |i| i.next }.to_proc)

# Procs can be bound to variables and used elsewhere
x = Proc.new { |i| i.next }
[1,2,3].map(&x)