Hi, I couldn't figure out, why I'm failing with attoparsec. I have the follwing code (https://github.com/michelk/devsurf/tree/readNet) import Data.Attoparsec.Text import qualified Data.Text as T import Language.DevSurf.Readers.SpringNet import Prelude hiding (takeWhile, take) data IndexedFace = IndexedFaceTriangle Int Int Int | IndexedFaceQuad Int Int Int Int deriving (Show) -- | block of faces-lines faces :: Parser [[(Int, IndexedFace)]] faces = faceLine `sepBy` endOfLine -- | Line containing up to two indexed faces faceLine :: Parser [(Int, IndexedFace)] faceLine = face `sepBy` (take 6) -- | single indexed-face face :: Parser (Int, IndexedFace) face = do i <- index v1 <- index v2 <- index v3 <- index v4 <- index case v4 of 0 -> return (i, IndexedFaceTriangle v1 v2 v3) _ -> return (i, IndexedFaceQuad v1 v2 v3 v4) -- | node or face index 6 wide index :: Parser Int index = do i <- take 6 return . read . T.unpack $ i When testing, the follwing is working: testEleL2 = do let ele = T.pack " 1 10 1 9 0 2 1 2 9 0\n" r = parse faceLine ele case r of Partial _ -> print $ feed r (T.pack "") _ -> print r testEles = do let eles = T.pack $ concat [" 1 10 1 9 0 2 1 2 9 0\n" --," 3 11 9 2 0\n" ," 4 12 8 1 0\n" ] r = parse faces eles case r of Partial _ -> print $ feed r (T.pack "") _ -> print r testEles = do let eles = T.pack $ concat [" 1 10 1 9 0 2 1 2 9 0\n" ," 3 11 9 2 0\n" --," 4 12 8 1 0\n" ] r = parse faces eles case r of Partial _ -> print $ feed r (T.pack "") _ -> print r But this is not working testEles = do let eles = T.pack $ concat [" 1 10 1 9 0 2 1 2 9 0\n" ," 3 11 9 2 0\n" ," 4 12 8 1 0\n" ] r = parse faces eles case r of Partial _ -> print $ feed r (T.pack "") _ -> print r testEles = do let eles = T.pack $ concat [" 1 10 1 9 0 2 1 2 9 0\n" ," 3 11 9 2 0 4 12 8 1 0\n" ] r = parse faces eles case r of Partial _ -> print $ feed r (T.pack "") _ -> print r Please help. Thanks, Michel
Hi Michel
I think you are reading empty string inside index function. I figured out
little bit and some where you are reading empty string but could not
concentrate enough ( or expert enough :) ) to see more because you are
parsing you code based on counting the number of characters ( take 6 inside
index function ).
*Main> read ""::Int
*** Exception: Prelude.read: no parse
Except the first test case, I changed the space between 0 and 2 ( for last
test case, I reduced the space between 0 and 4 ) to seven and now it's not
parsing completely but there is no error.
I have posted the code on ideone[1]. Here is the output on my system. I
have also attached the code.
*Main> :load "/Users/mukeshtiwari/Programming/Haskell/ParsingAtto.hs"
[1 of 1] Compiling Main (
/Users/mukeshtiwari/Programming/Haskell/ParsingAtto.hs, interpreted )
Ok, modules loaded: Main.
*Main> test1
Done "\n" [(1,IndexedFaceTriangle 10 1 9),(2,IndexedFaceTriangle 1 2 9)]
*Main> test2
Done " 12 8 1 0\n" [[(1,IndexedFaceTriangle 10 1
9),(2,IndexedFaceTriangle 1 2 9),(11,IndexedFaceQuad 9 2 0 4)]]
*Main> test3
Done " 12 8 1 0\n" [[(1,IndexedFaceTriangle 10 1
9),(2,IndexedFaceTriangle 1 2 9),(11,IndexedFaceQuad 9 2 0 4)]]
*Main> test4
Done " 12 8 1 0\n" [[(1,IndexedFaceTriangle 10 1
9),(2,IndexedFaceTriangle 1 2 9),(11,IndexedFaceQuad 9 2 0 4)]]
*Main> test5
Done " 12 8 1 0\n" [[(1,IndexedFaceTriangle 10 1
9),(2,IndexedFaceTriangle 1 2 9),(11,IndexedFaceQuad 9 2 0 4)]]
[1] http://ideone.com/x75C3j
Mukesh Tiwari
On Tue, Apr 9, 2013 at 11:30 AM, Michel Kuhlmann
Hi, I couldn't figure out, why I'm failing with attoparsec. I have the follwing code (https://github.com/michelk/devsurf/tree/readNet)
import Data.Attoparsec.Text import qualified Data.Text as T import Language.DevSurf.Readers.SpringNet import Prelude hiding (takeWhile, take)
data IndexedFace = IndexedFaceTriangle Int Int Int | IndexedFaceQuad Int Int Int Int deriving (Show)
-- | block of faces-lines faces :: Parser [[(Int, IndexedFace)]] faces = faceLine `sepBy` endOfLine
-- | Line containing up to two indexed faces faceLine :: Parser [(Int, IndexedFace)] faceLine = face `sepBy` (take 6)
-- | single indexed-face face :: Parser (Int, IndexedFace) face = do i <- index v1 <- index v2 <- index v3 <- index v4 <- index case v4 of 0 -> return (i, IndexedFaceTriangle v1 v2 v3) _ -> return (i, IndexedFaceQuad v1 v2 v3 v4)
-- | node or face index 6 wide index :: Parser Int index = do i <- take 6 return . read . T.unpack $ i
When testing, the follwing is working:
testEleL2 = do let ele = T.pack " 1 10 1 9 0 2 1 2 9 0\n" r = parse faceLine ele case r of Partial _ -> print $ feed r (T.pack "") _ -> print r
testEles = do let eles = T.pack $ concat [" 1 10 1 9 0 2 1 2 9 0\n" --," 3 11 9 2 0\n" ," 4 12 8 1 0\n" ] r = parse faces eles case r of Partial _ -> print $ feed r (T.pack "") _ -> print r
testEles = do let eles = T.pack $ concat [" 1 10 1 9 0 2 1 2 9 0\n" ," 3 11 9 2 0\n" --," 4 12 8 1 0\n" ] r = parse faces eles case r of Partial _ -> print $ feed r (T.pack "") _ -> print r
But this is not working
testEles = do let eles = T.pack $ concat [" 1 10 1 9 0 2 1 2 9 0\n" ," 3 11 9 2 0\n" ," 4 12 8 1 0\n" ] r = parse faces eles case r of Partial _ -> print $ feed r (T.pack "") _ -> print r
testEles = do let eles = T.pack $ concat [" 1 10 1 9 0 2 1 2 9 0\n" ," 3 11 9 2 0 4 12 8 1 0\n" ] r = parse faces eles case r of Partial _ -> print $ feed r (T.pack "") _ -> print r
Please help. Thanks, Michel
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