dLobatog/gist:5853677

## gistfile1.rb
sum = lambda do |f,a,b|
  s = 0; a.upto(b){|n| s += f.(n) } ; s
end

#Square all numbers from a to b and sum them.
sum.(lambda{|x| x**2},1,5) #=> 55
#This is probably the above in idiomatic Ruby
(1..5).map { |x| x**2 }.reduce(:+) #=> 55
	sum = lambda do \|f,a,b\|
	s = 0; a.upto(b){\|n\| s += f.(n) } ; s
	end

	#Square all numbers from a to b and sum them.
	sum.(lambda{\|x\| x**2},1,5) #=> 55
	#This is probably the above in idiomatic Ruby
	(1..5).map { \|x\| x**2 }.reduce(:+) #=> 55