Golf w/ comments

tc04Comments.hs

import Data.List 		-- gets us the function "intersect"
import System.Environment	-- gets us the function "getArgs"

f=concat.r 			-- calls "r" on some input and flattens the results (concat) 

{- The function "r" takes a list of elements and produces all of it's possible sublists.
Base case: If the input list is empty, return an empty list containing a single empty list. -}
r []=[[]]			-- base case for "r"
							
r s= (scanr(:)[]s) 		{-  recursively build substrings from the list "s" 
				and push them to an empty list                  -}
     :				-- Append the list we just built to...
     (r$init s)     		-- "r" called on the first n-1 elements of of the current list "s"

g [a,b]=snd.maximum.		-- finds the maximum by the length of strings
	map(\x->(length x, x))	-- groups lists into tuples of their lengths and the list
	$intersect(f a)(f b) 	-- The intersection* of "f" called on a, and "f" called on b
		
main= getArgs >>= 		-- get the command line arguments as a list ["firstString", "secondString"]
      \z-> print.g$z 		-- bind the argument list (z) to print "g" called on z