dzfl · June 10, 2010 17:15
diff --git a/reverse_polish_notation.rb b/reverse_polish_notation.rb
 #!/usr/bin/env ruby

 while $_ = gets
  a ||= []
  if /\d/ ~= $_
    a << $_.to_i
  end
  if /([-+*\/])/ ~= $_
    a << eval([a.pop, a.pop].reverse.join($1)
    puts a[-1]
  end
 end

 # klm is cool
 # ruby -ne'a||=[];~/\d/&&a<<$_.to_i;~/([-+*\/])/&&a<<eval([a.pop,a.pop].reverse.join $1)and puts a[-1]'
	#!/usr/bin/env ruby

	while $_ = gets
	a \|\|= []
	if /\d/ ~= $_
	a << $_.to_i
	end
	if /([-+*\/])/ ~= $_
	a << eval([a.pop, a.pop].reverse.join($1)
	puts a[-1]
	end
	end

	# klm is cool
	# ruby -ne'a\|\|=[];~/\d/&&a<<$_.to_i;~/([-+*\/])/&&a<<eval([a.pop,a.pop].reverse.join $1)and puts a[-1]'