diff --git a/http/attoparsec/.gitignore b/http/attoparsec/.gitignore
index 8ee1bf9..0c34f41 100644
--- a/http/attoparsec/.gitignore
+++ b/http/attoparsec/.gitignore
@@ -1 +1,3 @@
 .stack-work
+dist-newstyle
+tags
diff --git a/http/attoparsec/src/Main.hs b/http/attoparsec/src/Main.hs
index aea9cd6..f4710a9 100644
--- a/http/attoparsec/src/Main.hs
+++ b/http/attoparsec/src/Main.hs
@@ -1,25 +1,45 @@
 {-# LANGUAGE OverloadedStrings #-}
 
-import           Criterion.Main                   (bench, bgroup, defaultMain, env, whnf)
+import           Criterion.Main                   (bench, defaultMain, env, whnf)
 import qualified Data.ByteString                  as B
 
 import           Control.Applicative
 import           Data.Attoparsec.ByteString       as P
-import           Data.Attoparsec.ByteString.Char8 (char8, endOfLine, isDigit_w8)
-import           Data.Attoparsec.ByteString.Char8 (isEndOfLine, isHorizontalSpace)
+import           Data.Attoparsec.ByteString.Char8 (char8, endOfLine, isDigit_w8, isEndOfLine, isHorizontalSpace)
 import           Data.ByteString                  (ByteString)
 import           Data.Word                        (Word8)
 
 isToken :: Word8 -> Bool
-isToken w = w <= 127 && notInClass "\0-\31()<>@,;:\\\"/[]?={} \t" w
+isToken w =
+  w <= 127
+    && w > 31 -- "\0-\31"
+    && ( w /= 40 -- "("
+           && w /= 41 -- ")"
+           && w /= 60 -- "<"
+           && w /= 62 -- ">"
+           && w /= 64 -- "@"
+           && w /= 44 -- ","
+           && w /= 59 -- ";"
+           && w /= 58 -- ":"
+           && w /= 92 -- "\\"
+           && w /= 34 -- "\""
+           && w /= 91 -- "["
+           && w /= 93 -- "]"
+           && w /= 63 -- "?"
+           && w /= 61 -- "="
+           && w /= 123 -- "{"
+           && w /= 125 -- "}"
+           && w /= 32 -- " "
+           && w /= 9 -- "\t")
+       )
 
 skipSpaces :: Parser ()
 skipSpaces = satisfy isHorizontalSpace *> skipWhile isHorizontalSpace
 
 data Request = Request {
-      requestMethod  :: ByteString
-    , requestUri     :: ByteString
-    , requestVersion :: ByteString
+      requestMethod  :: !ByteString
+    , requestUri     :: !ByteString
+    , requestVersion :: !ByteString
     } deriving (Eq, Ord, Show)
 
 httpVersion :: Parser ByteString
@@ -31,15 +51,15 @@ requestLine = Request <$> (takeWhile1 isToken <* char8 ' ')
                       <*> (httpVersion <* endOfLine)
 
 data Header = Header {
-      headerName  :: ByteString
-    , headerValue :: [ByteString]
+      headerName  :: !ByteString
+    , headerValue :: ![ByteString]
     } deriving (Eq, Ord, Show)
 
 messageHeader :: Parser Header
 messageHeader = Header
   <$> (P.takeWhile isToken <* char8 ':' <* skipWhile isHorizontalSpace)
   <*> ((:) <$> (takeTill isEndOfLine <* endOfLine)
-           <*> (many $ skipSpaces *> takeTill isEndOfLine <* endOfLine))
+           <*> many ( skipSpaces *> takeTill isEndOfLine <* endOfLine))
 
 request :: Parser (Request, [Header])
 request = (,) <$> requestLine <*> many messageHeader <* endOfLine
@@ -53,19 +73,10 @@ smallFile = "../http-requests.txt"
 biggerFile :: FilePath
 biggerFile = "../bigger.txt"
 
-setupEnv :: IO (ByteString, ByteString)
-setupEnv = do
-  small  <- B.readFile smallFile
-  bigger <- B.readFile biggerFile
-  return (small, bigger)
-
 main :: IO ()
 main = defaultMain
-    [
-      env setupEnv $ \ ~(small, bigger) ->
-      bgroup "IO"
-        [
-          bench "small"          $ whnf (P.parseOnly allRequests) small
-        , bench "bigger"         $ whnf (P.parseOnly allRequests) bigger
-        ]
+    [ env (B.readFile smallFile) $ \small ->
+        bench "small" $ whnf (P.parseOnly allRequests) small,
+      env (B.readFile biggerFile) $ \big ->
+        bench "big" $ whnf (P.parseOnly allRequests) big
     ]