Portability | portable |
---|---|
Stability | provisional |
Maintainer | Sigbjorn Finne <sof@galois.com> |
Text.JSON
Contents
Description
- data JSValue
- class JSON a where
- data Result a
- encode :: JSON a => a -> String
- decode :: JSON a => String -> Result a
- encodeStrict :: JSON a => a -> String
- decodeStrict :: JSON a => String -> Result a
- data JSString
- toJSString :: String -> JSString
- fromJSString :: JSString -> String
- data JSObject e
- toJSObject :: [(String, a)] -> JSObject a
- fromJSObject :: JSObject e -> [(String, e)]
- resultToEither :: Result a -> Either String a
- readJSNull :: GetJSON JSValue
- readJSBool :: GetJSON JSValue
- readJSString :: GetJSON JSValue
- readJSRational :: GetJSON Rational
- readJSArray :: GetJSON JSValue
- readJSObject :: GetJSON JSValue
- readJSValue :: GetJSON JSValue
- showJSNull :: ShowS
- showJSBool :: Bool -> ShowS
- showJSArray :: [JSValue] -> ShowS
- showJSRational :: Rational -> ShowS
- showJSRational' :: Bool -> Rational -> ShowS
- showJSObject :: JSObject JSValue -> ShowS
- showJSValue :: JSValue -> ShowS
- makeObj :: [(String, JSValue)] -> JSValue
- valFromObj :: JSON a => String -> JSObject JSValue -> Result a
JSON Types
data JSValue
JSON values
The type to which we encode Haskell values. There's a set of primitives, and a couple of heterogenous collection types.
Objects:
An object structure is represented as a pair of curly brackets surrounding zero or more name/value pairs (or members). A name is a string. A single colon comes after each name, separating the name from the value. A single comma separates a value from a following name.
Arrays:
An array structure is represented as square brackets surrounding zero or more values (or elements). Elements are separated by commas.
Only valid JSON can be constructed this way
Serialization to and from JSValues
class JSON a where
The class of types serialisable to and from JSON
Instances
JSON Bool | |
JSON Char | |
JSON Double | |
JSON Float | |
JSON Int | |
JSON Int8 | |
JSON Int16 | |
JSON Int32 | |
JSON Int64 | |
JSON Integer | |
JSON Ordering | |
JSON Word | |
JSON Word8 | |
JSON Word16 | |
JSON Word32 | |
JSON Word64 | |
JSON () | |
JSON JSString | |
JSON JSValue | To ensure we generate valid JSON, we map Haskell types to JSValue internally, then pretty print that. |
JSON ByteString | |
JSON ByteString | |
JSON IntSet | |
JSON a => JSON [a] | |
JSON a => JSON (Maybe a) | |
JSON a => JSON (JSObject a) | |
(Ord a, JSON a) => JSON (Set a) | |
JSON a => JSON (IntMap a) | |
(JSON a, JSON b) => JSON (Either a b) | |
(JSON a, JSON b) => JSON (a, b) | |
(Ix i, JSON i, JSON e) => JSON (Array i e) | |
(Ord a, JSON a, JSON b) => JSON (Map a b) | |
(JSON a, JSON b, JSON c) => JSON (a, b, c) | |
(JSON a, JSON b, JSON c, JSON d) => JSON (a, b, c, d) |
Encoding and Decoding
data Result a
A type for parser results
encode :: JSON a => a -> String
Encode a Haskell value into a string, in JSON format.
This is a superset of JSON, as types other than Array and Object are allowed at the top level.
decode :: JSON a => String -> Result a
Decode a String representing a JSON value (either an object, array, bool, number, null)
This is a superset of JSON, as types other than Array and Object are allowed at the top level.
encodeStrict :: JSON a => a -> String
Encode a value as a String in strict JSON format. This follows the spec, and requires all values at the top level to be wrapped in either an Array or Object. JSON types to be an Array or Object.
decodeStrict :: JSON a => String -> Result a
Decode a String representing a strict JSON value. This follows the spec, and requires top level JSON types to be an Array or Object.
Wrapper Types
data JSString
Strings can be represented a little more efficiently in JSON
toJSString :: String -> JSString
Turn a Haskell string into a JSON string.
fromJSString :: JSString -> String
data JSObject e
As can association lists
toJSObject :: [(String, a)] -> JSObject a
Make JSON object out of an association list.
fromJSObject :: JSObject e -> [(String, e)]
resultToEither :: Result a -> Either String a
Map Results to Eithers
Serialization to and from Strings.
Reading JSON
Read the JSON null type
Read the JSON Bool type
readJSString :: GetJSON JSValue
Read the JSON String type
readJSRational :: GetJSON Rational
Read an Integer or Double in JSON format, returning a Rational
readJSArray :: GetJSON JSValue
Read a list in JSON format
readJSObject :: GetJSON JSValue
Read an object in JSON format
readJSValue :: GetJSON JSValue
Read one of several possible JS types
Writing JSON
showJSNull :: ShowS
Write the JSON null type
showJSBool :: Bool -> ShowS
Write the JSON Bool type
showJSArray :: [JSValue] -> ShowS
Show a list in JSON format
showJSRational :: Rational -> ShowS
Show a Rational in JSON format
showJSRational' :: Bool -> Rational -> ShowS
showJSObject :: JSObject JSValue -> ShowS
Show an association list in JSON format
showJSValue :: JSValue -> ShowS
Show JSON values
Instance helpers
valFromObj :: JSON a => String -> JSObject JSValue -> Result a
Pull a value out of a JSON object.