Data.Aeson.Pointer

Parsing, rendering, and traversing of RFC 6901 JSON pointers

Documentation

>>> import URI.ByteString.QQ
>>> :set -XOverloadedStrings
>>> :set -XQuasiQuotes
>>> :{
let sampleDoc = object
      [ "foo" .= ["bar" :: T.Text, "baz"]
      , "" .= (0 :: Int)
      , "a/b" .= (1 :: Int)
      , "c%d" .= (2 :: Int)
      , "e^f" .= (3 :: Int)
      , "g|h" .= (4 :: Int)
      , "i\\j" .= (5 :: Int)
      , "k\"l" .= (6 :: Int)
      , " " .= (7 :: Int)
      , "m~n" .= (8 :: Int)
      ]
:}

>>> let samplePointerText = "/data/foo" :: T.Text
>>> :{
let extractPointerValue = case parsePointer samplePointerText of
      Left err -> Nothing
      Right ptr ->
        (object ["data" .= object ["foo" .= 5.2]]) ^? pointerTraversal ptr
in extractPointerValue
:}
Just (Number 5.2)

>>> sampleDoc ^? pointerTraversal [jsonPtr||]
Just (Object (fromList [("c%d",Number 2.0),("m~n",Number 8.0),("e^f",Number 3.0),("",Number 0.0),(" ",Number 7.0),("foo",Array [String "bar",String "baz"]),("a/b",Number 1.0),("i\\j",Number 5.0),("k\"l",Number 6.0),("g|h",Number 4.0)]))
>>> sampleDoc ^? pointerTraversal [jsonPtr|/foo|]
Just (Array [String "bar",String "baz"])
>>> sampleDoc ^? pointerTraversal [jsonPtr|/foo/0|]
Just (String "bar")
>>> sampleDoc ^? pointerTraversal [jsonPtr|/foo/4|]
Nothing
>>> sampleDoc ^? pointerTraversal [jsonPtr|/|]
Just (Number 0.0)
>>> sampleDoc ^? pointerTraversal [jsonPtr|/a~1b|]
Just (Number 1.0)
>>> sampleDoc ^? pointerTraversal [jsonPtr|/c%d|]
Just (Number 2.0)
>>> sampleDoc ^? pointerTraversal [jsonPtr|/e^f|]
Just (Number 3.0)
>>> sampleDoc ^? pointerTraversal [jsonPtr|/g|h|]
Just (Number 4.0)
>>> sampleDoc ^? pointerTraversal [jsonPtr|/i\j|]
Just (Number 5.0)
>>> sampleDoc ^? pointerTraversal [jsonPtr|/k"l|]
Just (Number 6.0)
>>> sampleDoc ^? pointerTraversal [jsonPtr|/ |]
Just (Number 7.0)
>>> sampleDoc ^? pointerTraversal [jsonPtr|/m~0n|]
Just (Number 8.0)
>>> sampleDoc ^? pointerTraversal [jsonPtr|/woo|]
Nothing
>>> sampleDoc ^? pointerTraversal [jsonPtr|/m~0n/woo|]
Nothing
>>> parseURIFragment [relativeRef|#/c%25d|]
Right (JsonPointer {pointerSegments = [TextSegment "c%d"]})

data JsonPointer

Instances

Eq JsonPointer

Defined in Data.Aeson.Pointer

Methods

(==) :: JsonPointer -> JsonPointer -> Bool

(/=) :: JsonPointer -> JsonPointer -> Bool

Show JsonPointer

Defined in Data.Aeson.Pointer

Methods

showsPrec :: Int -> JsonPointer -> ShowS

show :: JsonPointer -> String

showList :: [JsonPointer] -> ShowS

Semigroup JsonPointer

Defined in Data.Aeson.Pointer

Methods

(<>) :: JsonPointer -> JsonPointer -> JsonPointer

sconcat :: NonEmpty JsonPointer -> JsonPointer

stimes :: Integral b => b -> JsonPointer -> JsonPointer

Monoid JsonPointer

Defined in Data.Aeson.Pointer

Methods

mempty :: JsonPointer

mappend :: JsonPointer -> JsonPointer -> JsonPointer

mconcat :: [JsonPointer] -> JsonPointer

Lift JsonPointer

Defined in Data.Aeson.Pointer

Methods

lift :: JsonPointer -> Q Exp

ToJSON JsonPointer

Defined in Data.Aeson.Pointer

Methods

toJSON :: JsonPointer -> Value

toEncoding :: JsonPointer -> Encoding

toJSONList :: [JsonPointer] -> Value

toEncodingList :: [JsonPointer] -> Encoding

FromJSON JsonPointer

Defined in Data.Aeson.Pointer

Methods

parseJSON :: Value -> Parser JsonPointer

parseJSONList :: Value -> Parser [JsonPointer]

mkJsonPointer :: [PointerSegment] -> JsonPointer

pointerSegments :: JsonPointer -> [PointerSegment]

jsonPtr :: QuasiQuoter

Parse a JSON Pointer at compile time and embed as an expression.

>>> [jsonPtr|/foo/0|]
JsonPointer {pointerSegments = [TextSegment "foo",TextOrNumberSegment "0" 0]}

parsePointer :: Text -> Either String JsonPointer

Parse a pointer from Text into a JsonPointer

parseURIFragment :: URIRef a -> Either String JsonPointer

renderPointer :: JsonPointer -> Text

Render a JsonPointer back into its RFC 6901 machine-readable format:

>>> renderPointer [jsonPtr|/~1/~0/woo|]
"/~1/~0/woo"

Simple pointer access

valueAt :: JsonPointer -> Value -> Maybe Value

overValueAt :: JsonPointer -> Value -> (Value -> Value) -> Value

Traversing JSON Documents

pointerTraversal :: JsonPointer -> Traversal' Value Value

segmentTraversal :: PointerSegment -> Traversal' Value Value

Segments

data PointerSegment

Instances

Eq PointerSegment

Defined in Data.Aeson.Pointer

Methods

(==) :: PointerSegment -> PointerSegment -> Bool

(/=) :: PointerSegment -> PointerSegment -> Bool

Show PointerSegment

Defined in Data.Aeson.Pointer

Methods

showsPrec :: Int -> PointerSegment -> ShowS

show :: PointerSegment -> String

showList :: [PointerSegment] -> ShowS

Lift PointerSegment

Defined in Data.Aeson.Pointer

Methods

lift :: PointerSegment -> Q Exp

unsafeTextSegment :: Text -> PointerSegment

Construct a PointerSegment from a Text value. The value must not be an Integer.

unsafeTextOrNumberSegment :: Int -> PointerSegment

Construct a PointerSegment from an Int value. The value must be greater than or equal to zero.

segmentText :: PointerSegment -> Text

Retrieve the text value of a pointer segment.

segmentNumber :: PointerSegment -> Maybe Int

Retrieve the numeric value of a pointer segment, if the segment can be interpreted as a number.

Parsers

pointerParser :: Parser JsonPointer

pointerSegmentParser :: Parser PointerSegment