procs, lambda, and blocks

blocks.rb

require 'active_support/all'


### We can send in a proc (or a lambda) for the method to call when we want it
###   to run. the proc behaves like a normal argument
$array = %w(apple banana kumquat)
def titlize_fruits(proc)

  proc.call $array.pop
  proc.call $array.pop
  proc.call $array.pop

end
titlize_fruits(Proc.new {|fruit| puts fruit.titleize})


### We can also send in a block
###   * All methods can receive 1 (and only 1) block
###   * We yield control to the block

$array = %w(apple banana kumquat)

def upcase_fruits

  yield $array.pop
  yield $array.pop
  yield $array.pop

end

upcase_fruits do |fruit|
  puts fruit.upcase
end


### We can also get access to the block and call it directly, like we would a proc


$array = %w(apple banana kumquat)

def hackerize_fruits(&block)

  block.call $array.pop
  block.call $array.pop
  block.call $array.pop

end


hackerize_fruits do |fruit|

  # We can also define a lambda as a variable
  hack_it = lambda {  |c|
    if [true,false].sample
      c.swapcase
    else
      c
    end
  }

  # and then send in the lambda to a method like `each`, `map`

  puts fruit.chars.map(&hack_it).join("")
end