{-# LANGUAGE PatternGuards, ScopedTypeVariables #-} {- Find bindings within a let, and lists of statements If you have n the same, error out main = do a; a; a; a main = do a; a; a; a; a; a -- ??? main = do a; a; a; a; a; a; a -- ??? main = do (do b; a; a; a); do (do c; a; a; a) -- ??? main = do a; a; a; b; a; a; a -- ??? main = do a; a; a; b; a; a foo = a where {a = 1; b = 2; c = 3}; bar = a where {a = 1; b = 2; c = 3} -- ??? -} module Hint.Duplicate(duplicateHint) where import Hint.Type import Control.Arrow import Data.List hiding (find) import qualified Data.Map as Map duplicateHint :: CrossHint duplicateHint ms = dupes [y | Do _ y :: Exp S <- universeBi modu] ++ dupes [y | BDecls l y :: Binds S <- universeBi modu] where modu = map snd ms dupes ys = [rawIdea (if length xs >= 5 then Error else Warning) "Reduce duplication" p1 (unlines \$ map (prettyPrint . fmap (const p1)) xs) ("Combine with " ++ showSrcLoc p2) "" | (p1,p2,xs) <- duplicateOrdered 3 \$ map (map (toSrcLoc . ann &&& dropAnn)) ys] --------------------------------------------------------------------- -- DUPLICATE FINDING -- | The position to return if we match at this point, and the map of where to go next -- If two runs have the same vals, always use the first pos you find data Dupe pos val = Dupe pos (Map.Map val (Dupe pos val)) find :: Ord val => [val] -> Dupe pos val -> (pos, Int) find (v:vs) (Dupe p mp) | Just d <- Map.lookup v mp = second (+1) \$ find vs d find _ (Dupe p mp) = (p, 0) add :: Ord val => pos -> [val] -> Dupe pos val -> Dupe pos val add pos [] d = d add pos (v:vs) (Dupe p mp) = Dupe p \$ Map.insertWith f v (add pos vs \$ Dupe pos Map.empty) mp where f new old = add pos vs old duplicateOrdered :: Ord val => Int -> [[(SrcLoc,val)]] -> [(SrcLoc,SrcLoc,[val])] duplicateOrdered threshold xs = concat \$ concat \$ snd \$ mapAccumL f (Dupe nullSrcLoc Map.empty) xs where f d xs = second overlaps \$ mapAccumL (g pos) d \$ takeWhile ((>= threshold) . length) \$ tails xs where pos = Map.fromList \$ zip (map fst xs) [0..] g pos d xs = (d2, res) where res = [(p,pme,take mx vs) | i >= threshold ,let mx = maybe i (\x -> min i \$ (pos Map.! pme) - x) \$ Map.lookup p pos ,mx >= threshold] vs = map snd xs (p,i) = find vs d pme = fst \$ head xs d2 = add pme vs d overlaps (x@((_,_,n):_):xs) = x : overlaps (drop (length n - 1) xs) overlaps (x:xs) = x : overlaps xs overlaps [] = []