module Data.Schematic.Path where
import Data.Foldable as F
import Data.Monoid
import Data.Schematic.Utils
import Data.Singletons
import Data.Singletons.Prelude
import Data.Singletons.TypeLits
import Data.Text as T
data PathSegment = Key Symbol | Ix Nat
data instance Sing (jp :: PathSegment) where
SKey :: (KnownSymbol k, Known (Sing k)) => Sing (k :: Symbol) -> Sing ('Key k)
SIx :: (KnownNat n, Known (Sing n)) => Sing (n :: Nat) -> Sing ('Ix n)
instance (KnownSymbol k, Known (Sing k))
=> Known (Sing ('Key k)) where
known = SKey known
instance (KnownNat n, Known (Sing n))
=> Known (Sing ('Ix n)) where
known = SIx known
data DemotedPathSegment = DKey Text | DIx Integer
deriving (Show)
newtype JSONPath = JSONPath Text
deriving (Show)
demotePath :: Sing (ps :: [PathSegment]) -> [DemotedPathSegment]
demotePath = go []
where
go :: [DemotedPathSegment] -> Sing (ps :: [PathSegment]) -> [DemotedPathSegment]
go acc SNil = acc
go acc (SCons p ps) = go (acc ++ [demote p]) ps
demote :: Sing (ps :: PathSegment) -> DemotedPathSegment
demote (SKey s) = DKey $ T.pack $ symbolVal s
demote (SIx n) = DIx $ natVal n
demotedPathToText :: [DemotedPathSegment] -> JSONPath
demotedPathToText = JSONPath . F.foldl' renderPathSegment ""
where
renderPathSegment acc (DKey t) = acc <> "." <> t
renderPathSegment acc (DIx n) = acc <> "[" <> T.pack (show n) <> "]"
pathToText :: Sing (ps :: [PathSegment]) -> JSONPath
pathToText = demotedPathToText . demotePath