refactored siphon type and improved testing

siphon/siphon.cabal

@@ -19,6 +19,7 @@ library
     Siphon.ByteString.Char8
     Siphon
     Siphon.Types
+    Siphon.Content
     Siphon.Encoding
     Siphon.Decoding
     Siphon.Internal
@@ -48,6 +49,9 @@ test-suite siphon-test
     , QuickCheck
     , text
     , bytestring
+    , pipes
+    , HUnit
+    , test-framework-hunit
   ghc-options:         -threaded -rtsopts -with-rtsopts=-N
   default-language:    Haskell2010
 

siphon/src/Siphon/Content.hs

@@ -0,0 +1,5 @@
+module Siphon.Content 
+  ( byteStringChar8
+  ) where
+
+import Siphon.Internal

siphon/src/Siphon/Decoding.hs

@@ -16,11 +16,6 @@ import qualified Data.Attoparsec.ByteString as AttoByteString
 import qualified Data.ByteString.Char8 as ByteString
 import qualified Data.Attoparsec.Types as Atto
 
-byteStringChar8 :: SiphonDecoding ByteString ByteString
-byteStringChar8 = SiphonDecoding
-  (AttoByteString.parse (row comma))
-  ByteString.null
-
 -- unrow :: c1 -> (Vector c2,c1)
 -- 
 -- row :: _
@@ -47,18 +42,18 @@ mkParseError i ctxs msg = id
 
 -- | This is seldom useful but is included for completeness.
 headlessPipe :: Monad m
-  => SiphonDecoding c1 c2 
-  -> Decoding Headless c2 a
-  -> Pipe c1 a m (DecodingRowError Headless c2)
+  => Siphon c
+  -> Decoding Headless c a
+  -> Pipe c a m (DecodingRowError Headless c)
 headlessPipe sd decoding = uncheckedPipe requiredLength 0 sd indexedDecoding Nothing
   where
   indexedDecoding = Decoding.headlessToIndexed decoding
   requiredLength = Decoding.length indexedDecoding
 
 indexedPipe :: Monad m
-  => SiphonDecoding c1 c2 
-  -> Decoding (Indexed Headless) c2 a
-  -> Pipe c1 a m (DecodingRowError Headless c2)
+  => Siphon c
+  -> Decoding (Indexed Headless) c a
+  -> Pipe c a m (DecodingRowError Headless c)
 indexedPipe sd decoding = do
   (firstRow, mleftovers) <- consumeGeneral sd mkParseError 
   let req = Decoding.maxIndex decoding
@@ -72,10 +67,10 @@ indexedPipe sd decoding = do
         uncheckedPipe vlen 1 sd decoding mleftovers
 
 
-headedPipe :: (Monad m, Eq c2)
-  => SiphonDecoding c1 c2 
-  -> Decoding Headed c2 a
-  -> Pipe c1 a m (DecodingRowError Headed c2)
+headedPipe :: (Monad m, Eq c)
+  => Siphon c
+  -> Decoding Headed c a
+  -> Pipe c a m (DecodingRowError Headed c)
 headedPipe sd decoding = do
   (headers, mleftovers) <- consumeGeneral sd mkParseError 
   case Decoding.headedToIndexed headers decoding of
@@ -88,10 +83,10 @@ headedPipe sd decoding = do
 uncheckedPipe :: Monad m
   => Int -- ^ expected length of each row
   -> Int -- ^ index of first row, usually zero or one
-  -> SiphonDecoding c1 c2 
-  -> Decoding (Indexed f) c2 a
-  -> Maybe c1
-  -> Pipe c1 a m (DecodingRowError f c2)
+  -> Siphon c 
+  -> Decoding (Indexed f) c a
+  -> Maybe c
+  -> Pipe c a m (DecodingRowError f c)
 uncheckedPipe requiredLength ix sd d mleftovers = 
   pipeGeneral ix sd mkParseError checkedRunWithRow mleftovers
   where
@@ -103,19 +98,19 @@ uncheckedPipe requiredLength ix sd d mleftovers =
       else Decoding.uncheckedRunWithRow rowIx d v
 
 consumeGeneral :: Monad m
-  => SiphonDecoding c1 c2
+  => Siphon c
   -> (Int -> [String] -> String -> e)
-  -> Consumer' c1 m (Vector c2, Maybe c1)
+  -> Consumer' c m (Vector c, Maybe c)
 consumeGeneral = error "ahh"
 
 pipeGeneral :: Monad m
   => Int -- ^ index of first row, usually zero or one
-  -> SiphonDecoding c1 c2 
+  -> Siphon c
   -> (Int -> [String] -> String -> e)
-  -> (Int -> Vector c2 -> Either e a)
-  -> Maybe c1 -- ^ leftovers that should be handled first
-  -> Pipe c1 a m e
-pipeGeneral initIx (SiphonDecoding parse isNull) wrapParseError decodeRow mleftovers = 
+  -> (Int -> Vector c -> Either e a)
+  -> Maybe c -- ^ leftovers that should be handled first
+  -> Pipe c a m e
+pipeGeneral initIx (Siphon _ _ parse isNull) wrapParseError decodeRow mleftovers = 
   case mleftovers of
     Nothing -> go1 initIx
     Just leftovers -> handleResult initIx (parse leftovers)

siphon/src/Siphon/Encoding.hs

@@ -6,24 +6,30 @@ import Pipes (Pipe,yield)
 import qualified Pipes.Prelude as Pipes
 import qualified Colonnade.Encoding as Encoding
 
-row :: Siphon c1 c2 
-    -> Encoding f c1 a 
+row :: Siphon c
+    -> Encoding f c a 
     -> a 
-    -> c2
-row (Siphon escape intercalate) e =
+    -> c
+row (Siphon escape intercalate _ _) e =
   intercalate . Encoding.runRow escape e
 
-header :: Siphon c1 c2 
-       -> Encoding Headed c1 a 
-       -> c2
-header (Siphon escape intercalate) e =
+header :: Siphon c
+       -> Encoding Headed c a 
+       -> c
+header (Siphon escape intercalate _ _) e =
   intercalate (Encoding.runHeader escape e)
 
-pipe :: Monad m => Siphon c1 c2 -> Encoding f c1 a -> Pipe a c2 m x
+pipe :: Monad m 
+  => Siphon c
+  -> Encoding f c a 
+  -> Pipe a c m x
 pipe siphon encoding = Pipes.map (row siphon encoding)
 
-pipeWithHeader :: Monad m => Siphon c1 c2 -> Encoding Headed c1 a -> Pipe a c2 m x
-pipeWithHeader siphon encoding = do
+headedPipe :: Monad m 
+  => Siphon c 
+  -> Encoding Headed c a 
+  -> Pipe a c m x
+headedPipe siphon encoding = do
   yield (header siphon encoding)
   pipe siphon encoding
 

siphon/src/Siphon/Internal.hs

@@ -29,31 +29,50 @@ import qualified Data.ByteString.Unsafe as S
 import qualified Data.Vector as V
 import qualified Data.ByteString as B
 import qualified Data.ByteString.Lazy as LByteString
+import qualified Data.ByteString.Builder as Builder
 import Data.Word (Word8)
 import Data.Vector (Vector)
 import Data.ByteString (ByteString)
+import Data.Coerce (coerce)
+import Siphon.Types
 
 import Control.Applicative
 import Data.Monoid
 
--- parse :: Monad m
---       => SiphonDecoding c1 c2
---       -> Atto.Parser a b -- ^ Attoparsec parser
---       -> Pipes.Parser a m (Maybe (Either ParsingError b)) -- ^ Pipes parser
--- parse parser = S.StateT $ \p0 -> do
---     x <- nextSkipEmpty p0
---     case x of
---       Left r       -> return (Nothing, return r)
---       Right (a,p1) -> step (yield a >>) (_parse parser a) p1
---   where
---     step diffP res p0 = case res of
---       Fail _ c m -> return (Just (Left (ParsingError c m)), diffP p0)
---       Done a b   -> return (Just (Right b), yield a >> p0)
---       Partial k  -> do
---         x <- nextSkipEmpty p0
---         case x of
---           Left e -> step diffP (k mempty) (return e)
---           Right (a,p1) -> step (diffP . (yield a >>)) (k a) p1
+byteStringChar8 :: Siphon ByteString
+byteStringChar8 = Siphon 
+  escape 
+  encodeRow
+  (A.parse (row comma))
+  B.null
+
+encodeRow :: Vector (Escaped ByteString) -> ByteString
+encodeRow = id
+  . flip B.append (B.singleton newline)
+  . B.intercalate (B.singleton comma)
+  . V.toList
+  . coerce
+
+escape :: ByteString -> Escaped ByteString
+escape t = case B.find (\c -> c == newline || c == comma || c == doubleQuote) t of
+  Nothing -> Escaped t
+  Just _  -> escapeAlways t
+
+-- | This implementation is definitely suboptimal.
+-- A better option (which would waste a little space
+-- but would be much faster) would be to build the
+-- new bytestring by writing to a buffer directly.
+escapeAlways :: ByteString -> Escaped ByteString
+escapeAlways t = Escaped $ LByteString.toStrict $ Builder.toLazyByteString $
+     Builder.word8 doubleQuote
+  <> B.foldl
+      (\ acc b -> acc <> if b == doubleQuote
+          then Builder.byteString
+            (B.pack [doubleQuote,doubleQuote])
+          else Builder.word8 b)
+      mempty
+      t
+  <> Builder.word8 doubleQuote
 
 -- | Specialized version of 'sepBy1'' which is faster due to not
 -- accepting an arbitrary separator.

siphon/src/Siphon/Text.hs

@@ -7,12 +7,13 @@ import Data.Coerce (coerce)
 import qualified Data.Text   as Text
 import qualified Data.Vector as Vector
 
-siphon :: Siphon Text Text
+siphon :: Siphon Text
 siphon = Siphon escape encodeRow
+  (error "siphon: uhoent") (error "siphon: uheokj")
 
 encodeRow :: Vector (Escaped Text) -> Text
 encodeRow = id
-  . Text.intercalate (Text.pack ",")
+  . Text.intercalate (Text.singleton ',')
   . Vector.toList
   . coerce
 

siphon/src/Siphon/Types.hs

@@ -5,12 +5,19 @@ import qualified Data.Attoparsec.Types as Atto
 
 newtype Escaped c = Escaped { getEscaped :: c }
 
+data Siphon c = Siphon
+  { siphonEscape      :: !(c -> Escaped c)
+  , siphonIntercalate :: !(Vector (Escaped c) -> c)
+  , siphonParseRow    :: c -> Atto.IResult c (Vector c)
+  , siphonNull        :: c -> Bool
+  }
+
 -- | Consider changing out the use of 'Vector' here
 -- with the humble list instead. It might fuse away
 -- better. Not sure though.
-data Siphon c1 c2 = Siphon
-  { siphonEscape :: !(c1 -> Escaped c2)
-  , siphonIntercalate :: !(Vector (Escaped c2) -> c2)
+data SiphonX c1 c2 = SiphonX
+  { siphonXEscape :: !(c1 -> Escaped c2)
+  , siphonXIntercalate :: !(Vector (Escaped c2) -> c2)
   }
 
 data SiphonDecoding c1 c2 = SiphonDecoding

siphon/test/Test.hs

@@ -1,11 +1,16 @@
+{-# LANGUAGE OverloadedStrings #-}
+
 module Main (main) where
 
 import Test.QuickCheck                      (Gen, Arbitrary(..), choose)
+import Test.HUnit                           (Assertion,(@?=))
 import Test.Framework                       (defaultMain, testGroup, Test)
 import Test.Framework.Providers.QuickCheck2 (testProperty)
+import Test.Framework.Providers.HUnit       (testCase)
 import Data.ByteString                      (ByteString)
 import Data.Either.Combinators
 import Colonnade.Types
+import Data.Functor.Identity
 import Data.Functor.Contravariant           (contramap)
 import Data.Functor.Contravariant.Divisible (divided,conquered)
 import qualified Data.ByteString.Builder    as Builder
@@ -14,21 +19,27 @@ import qualified Data.ByteString            as ByteString
 import qualified Data.ByteString.Char8      as BC8
 import qualified Colonnade.Decoding         as Decoding
 import qualified Colonnade.Encoding         as Encoding
+import qualified Siphon.Encoding            as SE
+import qualified Siphon.Decoding            as SD
+import qualified Siphon.Content             as SC
+import qualified Pipes.Prelude              as Pipes
+import Pipes
 
 main :: IO ()
 main = defaultMain tests
 
 tests :: [Test]
-tests = []
+tests =
   [ testGroup "ByteString encode/decode" 
-    [ testProperty "Headless Isomorphism (int,char,bool)" 
-        $ propEncodeDecodeIso 
-          (ipv4ToTextNaive) 
-          (ipv4FromTextNaive)
+    [ testCase "Headless Encoding (int,char,bool)" testEncodingA
+    , testProperty "Headless Isomorphism (int,char,bool)" 
+        $ propIsoPipe $
+          (SE.pipe SC.byteStringChar8 encodingA)
+          >->
+          (void $ SD.headlessPipe SC.byteStringChar8 decodingA)
     ]
   ]
 
-
 byteStringDecodeInt :: ByteString -> Either String Int
 byteStringDecodeInt b = do
   (a,bsRem) <- maybe (Left "could not parse int") Right (BC8.readInt b)
@@ -78,6 +89,16 @@ encodingA = contramap tripleToPairs
 tripleToPairs :: (a,b,c) -> (a,(b,(c,())))
 tripleToPairs (a,b,c) = (a,(b,(c,())))
 
+propIsoPipe :: Eq a => Pipe a a Identity () -> [a] -> Bool
+propIsoPipe p as = (Pipes.toList $ each as >-> p) == as
+
+testEncodingA :: Assertion
+testEncodingA = 
+  ( ByteString.concat $ Pipes.toList $ 
+    Pipes.yield (4,'c',False) >-> SE.pipe SC.byteStringChar8 encodingA
+  ) @?= "4,c,false\n"
+
+
 propEncodeDecodeIso :: Eq a => (a -> b) -> (b -> Maybe a) -> a -> Bool
 propEncodeDecodeIso f g a = g (f a) == Just a