{-# LANGUAGE OverloadedStrings #-}
module Main where
import Control.Monad (unless)
import Data.Aeson
import qualified Data.Aeson.Pointer as P
main :: IO ()
main = do
-- JSON Pointers must either be empty or start with a /.
pntr1 <- case P.unescape "/foo/0" of
Left _ -> error "Failed to construct JSON Pointer."
Right pntr -> pure pntr
-- We can also write JSON Pointers in Haskell.
let pntr2 = P.Pointer [P.Token "/"]
-- When we do this we don't have to escape / or ~ characters
-- (as ~1 and ~0 respectively) like we do in an escaped JSON
-- Pointer string.
unless (P.unescape "/~1" == Right pntr2) (error "ohno!")
print (P.resolve pntr1 document)
print (P.resolve pntr2 document)
where
document :: Value
document = object [ "foo" .= [String "bar", String "baz"]
, "/" .= String "quux"
]
Output:
Right (String "bar")
Right (String "quux")
Changes
0.3
Rewrite.
0.2
Fix mistake in resolveRefTok.
Split errors over two types.
Switch the order of pointer and value arguments for functions that take both. The pointer now comes first.
