mars rover problem in 3 lines of ruby 2 code

mars_rover.rb

IO.read('i').lines.drop(1).each_slice(2){|p,t|x,y,h=p.split;x,y,h=[x.to_i,y.to_i,h.to_sym];z={N:[->{y+=1},:W,:E],E:[->{
x+=1},:N,:S],S:[->{y-=1},:E,:W],W:[->{x-=1},:S,:N]};t.strip.split(//).map{|c|if c=='M';z[h][0].call;elsif c=='L';h=
z[h][1];else;h=z[h][2];end};puts"#{x} #{y} #{h}"}

The challenge: https://twitter.com/HeyHeySueEllen/status/311051492108939265

And a description of the problem, for those that are interested: http://www.technicalypto.com/2010/02/thoughtworks-mass-rovers-coding-problem.html