Example on how to use to_proc with Ruby classes

to_proc.rb

# class to test behaviour of Proc and to_proc
class ProcTest
  def initialize(text='')
    @text = text
  end

  def say
    puts "say #{text}"
  end

  attr_reader :text

  def to_proc
    ->(obj, *args) { obj.send(self, *args) }
  end

  def self.to_proc
    ->(*args) { new(*args) }
  end
end

# initial list of strings
list = ["hello", "json", "how", "are", "you"]

# create instances of ProcTest, each string used as argument, using Test.to_proc
list.map(&ProcTest)

# create instances of ProcTest and call on each instance the 'say' method, invoking Test#to_proc
list.map(&ProcTest).map(&:say)