deque-blog’s gists

deque-blog / testing_random_generated_clojure.clj

Created February 14, 2017 21:34

	(defn ptvkegely [c j m n t u y] (+ -64 m c t y n j u))
	=> #'user/ptvkegely

	(ptvkegely 1 2 3 4 5 6 7)
	=> -36

deque-blog / arithmetic_count_ast_nodes.hs

Created February 14, 2017 21:52

	countNodes :: Expr -> Int
	countNodes = cata countAlg where
	countAlg (Op _ xs) = 1 + sum xs
	countAlg _ = 1

deque-blog / length_and_count_of_expression.hs

Last active February 14, 2017 22:16

deque-blog / arithmetic_paramorphism.hs

Created February 15, 2017 21:20

	para :: (ExprR (a, Expr) -> a) -> Expr -> a
	para alg = alg . fmap (para alg &&& id) . unFix

deque-blog / arithmetic_prn_infix.hs

Created February 15, 2017 21:21

	prnInfix :: Expr -> String
	prnInfix = para infixAlg where

	infixAlg (Op Add xs) = concat (intersperse " + " (map fst xs))
	infixAlg (Op Mul xs) = concat (intersperse " * " (map parensPlus xs))
	infixAlg (Cst n) = show n
	infixAlg (Var v) = v

	parensPlus (s, Fix (Op Add _)) = "(" ++ s ++ ")"
	parensPlus (s, _) = s

deque-blog / arithmetic_prn_infix_example.hs

Created February 15, 2017 21:26

deque-blog / arithmetic_prefix_vs_infix_challenge.hs

Last active February 16, 2017 20:33

	data ContestResult = ContestResult {
	prefixScore :: Int ,
	infixScore :: Int }
	deriving (Show)

	runContest :: Int -> IO ()
	runContest size = do
	expressions <- generate (replicateM 1000 (genExpr size))
	let run printer = sum $ map (length . printer . optimize) expressions
	print $ ContestResult (run prn) (run prnInfix)

deque-blog / arithmetic_prefix_vs_infix_challenge_result.hs

Last active February 16, 2017 20:32

	runContest 30
	> ContestResult {prefixScore = 31951, infixScore = 42293}

	runContest 100
	> ContestResult {prefixScore = 87662, infixScore = 125822}

deque-blog / arithmetic_prn_infix_bad.hs

Last active February 16, 2017 19:50

	prnInfix :: Expr -> String
	prnInfix = cata infixAlg where

	infixAlg (Op Add xs) = concat (intersperse " + " xs)
	infixAlg (Op Mul xs) = concat (intersperse " * " (map parens xs))
	infixAlg (Cst n) = show n
	infixAlg (Var v) = v

	parens x = "(" ++ x ++ ")"

deque-blog / arithmetic_bad_prn_infix_example.hs

Created February 16, 2017 19:49