Applied lots of hints, mostly redundant brackets

src/MdToHTML.hs

@@ -1,3 +1,5 @@
+{-# LANGUAGE InstanceSigs #-}
+
 module MdToHTML where
 
 import Control.Applicative
@@ -38,20 +40,21 @@ data MdToken
 
 -- Deriving Show for MdToken
 instance Show MdToken where
-  show (Document tokens) = concat (map show tokens)
+  show :: MdToken -> String
+  show (Document tokens) = concatMap show tokens
   show (Header level token) = "<h" ++ show level ++ ">" ++ show token ++ "</h" ++ show level ++ ">"
   show (Para token) = "<p>" ++ show token ++ "</p>"
-  show (Line tokens) = concat (map show tokens)
+  show (Line tokens) = concatMap show tokens
   show Linebreak = "<br>"
   show SingleNewline = " "
   show HorizontalRule = "---------"
   show (Blockquote token) = "BLOCK" ++ show token
-  show (UnordList tokens) = "UNORD" ++ concat (map show tokens)
-  show (OrdList tokens) = "ORD" ++ concat (map show tokens)
+  show (UnordList tokens) = "UNORD" ++ concatMap show tokens
+  show (OrdList tokens) = "ORD" ++ concatMap show tokens
   show (Code code) = show code
   show (Codeblock code) = show code
-  show (Link txt url) = "<a href=" ++ (getUrl url) ++ ">" ++ show txt ++ "</a>"
-  show (Image txt imgPath) = "<img src=" ++ (getPath imgPath) ++ ">" ++ show txt ++ "</img>"
+  show (Link txt url) = "<a href=" ++ getUrl url ++ ">" ++ show txt ++ "</a>"
+  show (Image txt imgPath) = "<img src=" ++ getPath imgPath ++ ">" ++ show txt ++ "</img>"
   show (Bold token) = "<b>" ++ show token ++ "</b>"
   show (Italic token) = "<i>" ++ show token ++ "</i>"
   show (Strikethrough token) = "<s>" ++ show token ++ "</s>"
@@ -61,8 +64,8 @@ instance Show MdToken where
 -- Helpers
 leftmostLongest :: (Foldable t) => [(a, t b)] -> (a, t b)
 leftmostLongest xs =
-  let lastElem = (last xs)
-      filteredLst = (filter (\val -> (length $ snd val) == (length $ snd lastElem)) xs)
+  let lastElem = last xs
+      filteredLst = filter (\val -> length (snd val) == length (snd lastElem)) xs
    in head filteredLst
 
 -- Get the first parse returned by readP_to_S that consumed the most input
@@ -88,7 +91,7 @@ parseHeader = do
   skipSpaces
   headers <- munch1 (== '#')
   when
-    ((length headers) > 6)
+    (length headers > 6)
     pfail
   skipSpaces
   text <- munch1 (/= '\n')
@@ -135,7 +138,7 @@ parseSingleNewline = do
 parseString :: ReadP MdToken
 parseString = do
   firstChar <- satisfy (/= '\n') -- Must parse at least one non-newline character here
-  text <- munch (\x -> not (elem x "#*_[\n "))
+  text <- munch (`notElem` "#*_[\n ")
   return (Unit (firstChar : text))
 
 lineParsers :: [ReadP MdToken]
@@ -164,7 +167,7 @@ parsePara = do
   parseMany (char '\n')
   --  text <- many1 (lookaheadParse (\x -> ((length x) < 2) || (take 2 x) /= "\n\n")) -- Parse until a double-newline.
   --  string "\n\n" <|> (eof >> return "") -- Consume the next double-newline or EOF.
-  text <- (manyTill get ((string "\n\n") <|> (eof >> return "")))
+  text <- manyTill get (string "\n\n" <|> (eof >> return ""))
   when (null text) pfail
   let parsedText = fst $ leftmostLongestParse parseLine text -- Parse either a line or a header.
   -- If the paragraph is a header, return a Header token. Otheriwse return a Para token.
@@ -175,5 +178,5 @@ parsePara = do
 -- Parse a document, which is multiple paragraphs.
 parseDocument :: ReadP MdToken
 parseDocument = do
-  res <- manyTill (parseHeader <++ parsePara) (eof)
+  res <- manyTill (parseHeader <++ parsePara) eof
   return (Document res)