commented last functions

pcp/pcp.hs

@@ -232,20 +232,25 @@ pcp = \x -> ycomb (\f x y ->
 
 -- PCP Problems
 
+-- [(a, ab), (bb, b)]
 problem_1 :: ListStrPairs
 problem_1 = cons (pair a ab) (cons (pair bb b) nil)
 
+-- [(a, abbb), (bb, b)]
 problem_2 :: ListStrPairs
 problem_2 = cons (pair a abbb) (cons (pair bb b) nil)
 
+-- [(bba, b), (b, ab), (a, bba)]
 problem_3 :: ListStrPairs -- undecidable
 problem_3 = cons (pair bba b) (cons (pair b ab) (cons (pair a bba) nil))
 
 -- PARSE LC ENCODINGS TO STRINGS
 
+-- string encoding to String
 lcstr_tostr :: LCStr -> String
 lcstr_tostr = \s -> unString s (\a -> "a" ++ a) (\b -> "b" ++ b) ("")
 
+-- bool encoding to String
 lcbool_tostr :: LCBool -> String
 lcbool_tostr = \b -> ite b "True" "False"