# If the last parameter in a method definition is prefixed with an ampersand, any associated block 
# is converted to a Proc object and that object is assigned to the parameter.
# It must be the last argument in the parameter list
def do_math_operation(amount, &block)
  block.call(amount) # OR yield(amount)
end

result = do_math_operation(5) {|amount| amount * 2}
 => 10

# A proc is a reusable object oriented block , a block is actually a proc that can't be saved
block.class => Proc

# The same above can be done using proc

def do_math_operation(amount, proc)
  proc.call(amount) # yield won't work!
end

multiply_by_2 = Proc.new do |n|
  n * 2
end

result = do_math_operation(5, multiply_by_2)
 => 10

# The same above can be done using lambda
def do_math_operation(amount, lambda)
  lambda.call(amount) # yield won't work!
end

multiply_by_2 = lambda{ |n| n * 2 }
result = do_math_operation(5, multiply_by_2)
 => 10

# Differences between Lambda and Procs
# 1- Lambda checks for number of parameters , throw an exception if less or more parameters were passed
# ex:
lambda = lambda{ |str1, str2| "#{str1}, #{str2}"}
lambda.call('str1', 'str2')
=> str1, str2
lambda.call('str2','str2','str3')
ArgumentError: wrong number of arguments (3 for 2)

proc = Proc.new{ |str1, str2| "#{str1}, #{str2}" }
proc.call("str1")
=> str1, 

# 2- Lambda in a method will return the value to the method and the method continues normally, while Proc stops method execution

def proc_return
  Proc.new{ |n| puts n }
  puts 'see me if you can'
end

def lambda_return
  lambda{ |n| puts n }
  puts 'hi, i am here'
end

proc_return
=> Proc
lambda_return
=> hi, i am here

# Note proc can't have a return in it , while lambda can

# The same can be done using method objects
def do_math_operation(amount, method)
  block.call(amount) # yield won't work!
end

def multiply_by_2(n)
  n * 2
end

result = do_math_operation(5, method(:multiply_by_2))
 => 10

# Method objects will act like lambda , only lambda is anonymous