gistfile1.rbx

numbers = %w{1.3 1.5 1.8}

puts "# 1 - standard stuff"
p numbers.map { |x| x.to_f }

puts "# 2 - passing in a proc using &"
to_f_proc = proc { |x| x.to_f }
p numbers.map(&to_f_proc)

puts "# 3 - passing in a dynamic proc"
def sender method
  proc { |x| x.send(method) }
end
p numbers.map(&sender(:to_f))

puts "# 4 - ruby automagically calls to_proc on what's passed in as the block"
class Sender
  def initialize sym
    @sym
  end
  def to_proc
    proc { |x| x.send(@sym) }
  end
end
p numbers.map(&Sender.new(:to_f))

puts "# 5 - monkey patching it onto symbol"
class Symbol
  def to_proc
    proc { |x| x.send(self) }
  end
end
p numbers.map(&:to_f)