I was trying this but ran into a bit of trouble. Are you super attached to that data structure? I would expect a radix tree as you've described it to look more like this: data RadixTree = Node [(Text, RadixTree)] | Leaf Times data Times = Times (Maybe Int) (Maybe Int) In which case it is much easier to write the json instances. From there you shouldn't have too much of a problem writing a recursive function to do the rest, without dealing with all the aeson stuff at the same time. Here's what I ended up with (I think it could be cleaned up a bit). import Control.Monad import Data.Text as T import Data.Aeson import Data.HashMap.Strict as HM import Data.Vector as V hiding (mapM) data RadixTree = Node [(Text, RadixTree)] | Leaf Times deriving Show data Times = Times (Maybe Int) (Maybe Int) deriving Show instance FromJSON RadixTree where parseJSON (Object o) = do let els = HM.toList o contents <- mapM (\(t,v) -> do v' <- parseJSON v; return (t, v')) (HM.toList o) return $ Node contents parseJSON a@(Array _) = Leaf <$> parseJSON a parseJSON _ = mzero instance FromJSON Times where parseJSON (Array v) | (V.length v) >= 2 = let v0 = v V.! 0 v1 = v V.! 1 in Times <$> parseJSON v0 <*> parseJSON v1 parseJSON _ = mzero {- tree2things :: RadixTree -> [(Text, (Maybe Int, Maybe Int))] tree2things (Node xs) = _ tree2things (Leaf t) = _ -} On Thu, Aug 27, 2015 at 11:30 AM, Adam Flott wrote:

On 08/27/2015 11:18 AM, Karl Voelker wrote:

...

On Thu, Aug 27, 2015, at 08:04 AM, Adam Flott wrote:

...

data Things = MkThings { thing :: TL.Text, times :: ThingTimes } deriving (Show, Eq, Typeable)

data ThingTimes = MkThingtimes { ml :: V.Vector Times } deriving (Show, Eq, Typeable)

data Times = MkTimes { t1 :: Maybe Int32, t2 :: Maybe Int32 } deriving (Show, Eq, Typeable)

-- radix.json -- { "a" : { "b" : [ 1, 2 ], "c" : { "d" : [ 3, null ] } }, "a2" : { "b2" : [ 4, 5 ] } } -- radix.json -- It looks like your input file has Things nested inside Things, but your data types don't allow for that. Is that intentional? What value is that example input supposed to parse to?

Vector [ MkThings "ab" (MkThingTimes (Vector [ Just 1, Just 2 ])), MkThings "abcd" (MkThingsTimes (Vector [ Just 3, Nothing)) MkThings "a2b2" (MkThingTimes (Vector [ Just 4, Just 5 ])) ] _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

Well I went ahead and completed that function, but I didn't use your data types exactly, but it should be a one to one mapping, just modify this function with your constructors. radix2things :: RadixTree -> [(Text, (Maybe Int, Maybe Int))] radix2things r = conv' mempty r where conv' :: Text -> RadixTree -> [(Text, (Maybe Int, Maybe Int))] conv' acc (Leaf (Times a b)) = [(acc, (a, b))] conv' acc r@(Node ns) = P.concatMap (\(t,r) -> conv' (acc <> t) r) ns And you'll get a result like: *Main> case decode teststr of Nothing -> undefined; Just a -> conv a [("a2b2",(Just 4,Just 5)),("ab",(Just 1,Just 2)),("acd",(Just 3,Nothing))] Good luck. On Thu, Aug 27, 2015 at 4:31 PM, Adam Flott wrote:

I am attached to the data structure as it's what our Thrift message spits out and has to be mapped that way for the down stream consumers.

On 08/27/2015 01:45 PM, David McBride wrote:

...

I was trying this but ran into a bit of trouble. Are you super attached to that data structure? I would expect a radix tree as you've described it to look more like this:

data RadixTree = Node [(Text, RadixTree)] | Leaf Times data Times = Times (Maybe Int) (Maybe Int)

In which case it is much easier to write the json instances. From there you shouldn't have too much of a problem writing a recursive function to do the rest, without dealing with all the aeson stuff at the same time. Here's what I ended up with (I think it could be cleaned up a bit).

import Control.Monad import Data.Text as T import Data.Aeson import Data.HashMap.Strict as HM import Data.Vector as V hiding (mapM)

data RadixTree = Node [(Text, RadixTree)] | Leaf Times deriving Show data Times = Times (Maybe Int) (Maybe Int) deriving Show

instance FromJSON RadixTree where parseJSON (Object o) = do let els = HM.toList o contents <- mapM (\(t,v) -> do v' <- parseJSON v; return (t, v')) (HM.toList o) return $ Node contents parseJSON a@(Array _) = Leaf <$> parseJSON a parseJSON _ = mzero

instance FromJSON Times where parseJSON (Array v) | (V.length v) >= 2 = let v0 = v V.! 0 v1 = v V.! 1 in Times <$> parseJSON v0 <*> parseJSON v1 parseJSON _ = mzero

{- tree2things :: RadixTree -> [(Text, (Maybe Int, Maybe Int))] tree2things (Node xs) = _ tree2things (Leaf t) = _ -}

On Thu, Aug 27, 2015 at 11:30 AM, Adam Flott mailto:adam@adamflott.com> wrote:

On 08/27/2015 11:18 AM, Karl Voelker wrote: > On Thu, Aug 27, 2015, at 08:04 AM, Adam Flott wrote: >> data Things = MkThings { >> thing :: TL.Text, >> times :: ThingTimes >> } deriving (Show, Eq, Typeable) >> >> data ThingTimes = MkThingtimes { >> ml :: V.Vector Times >> } deriving (Show, Eq, Typeable) >> >> data Times = MkTimes { >> t1 :: Maybe Int32, >> t2 :: Maybe Int32 >> } deriving (Show, Eq, Typeable) >> >> -- radix.json -- >> { >> "a" : { >> "b" : [ 1, 2 ], >> "c" : { >> "d" : [ 3, null ] >> } >> }, >> "a2" : { "b2" : [ 4, 5 ] } >> } >> -- radix.json -- > It looks like your input file has Things nested inside Things, but your > data types don't allow for that. Is that intentional? What value is that > example input supposed to parse to?

Vector [ MkThings "ab" (MkThingTimes (Vector [ Just 1, Just 2 ])), MkThings "abcd" (MkThingsTimes (Vector [ Just 3, Nothing)) MkThings "a2b2" (MkThingTimes (Vector [ Just 4, Just 5 ])) ] _______________________________________________ Beginners mailing list Beginners@haskell.org mailto:Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners