Data.Yaml

Provides a high-level interface for processing YAML files.

This module reuses most of the infrastructure from the aeson package. This means that you can use all of the existing tools for JSON processing for processing YAML files. As a result, much of the documentation below mentions JSON; do not let that confuse you, it's intentional.

For the most part, YAML content translates directly into JSON, and therefore there is very little data loss. If you need to deal with YAML more directly (e.g., directly deal with aliases), you should use the Text.Libyaml module instead.

For documentation on the aeson types, functions, classes, and operators, please see the Data.Aeson module of the aeson package.

Types

data Value :: *

Constructors

Object !Object

Array !Array

String !Text

Number !Scientific

Bool !Bool

Null

Instances

Eq Value

Data Value

Show Value

IsString Value

NFData Value

Hashable Value

ToJSON Value

FromJSON Value

Typeable * Value

data Parser a :: * -> *

Instances

Alternative Parser

Monad Parser

Functor Parser

MonadPlus Parser

Applicative Parser

Monoid (Parser a)

type Object = HashMap Text Value

type Array = Vector Value

data ParseException

Constructors

NonScalarKey

UnknownAlias

Fields

_anchorName :: AnchorName

UnexpectedEvent

Fields

_received :: Maybe Event

_expected :: Maybe Event

InvalidYaml (Maybe YamlException)

AesonException String

OtherParseException SomeException

NonStringKeyAlias AnchorName Value

CyclicIncludes

Instances

Show ParseException

Exception ParseException

Typeable * ParseException

prettyPrintParseException :: ParseException -> String

Alternative to show to display a ParseException on the screen. Instead of displaying the data constructors applied to their arguments, a more textual output is returned. For example, instead of printing:

AesonException "The key \"foo\" was not found"

It looks more pleasant to print:

Aeson exception: The key "foo" was not found

Since 0.8.11

data YamlException

Constructors

YamlException String

YamlParseException

problem, context, index, position line, position column

Fields

yamlProblem :: String

yamlContext :: String

yamlProblemMark :: YamlMark

Instances

Show YamlException

Exception YamlException

Typeable * YamlException

data YamlMark

The pointer position

Constructors

YamlMark

Fields

yamlIndex :: Int

yamlLine :: Int

yamlColumn :: Int

Instances

Show YamlMark

Constructors and accessors

object :: [Pair] -> Value

array :: [Value] -> Value

(.=) :: ToJSON a => Text -> a -> Pair

(.:) :: FromJSON a => Object -> Text -> Parser a

(.:?) :: FromJSON a => Object -> Text -> Parser (Maybe a)

(.!=) :: Parser (Maybe a) -> a -> Parser a

Parsing

parseMonad :: Monad m => (a -> Parser b) -> a -> m b

parseEither :: (a -> Parser b) -> a -> Either String b

parseMaybe :: (a -> Parser b) -> a -> Maybe b

Classes

class ToJSON a where

Minimal complete definition

Nothing

Methods

toJSON :: a -> Value

Instances

ToJSON Bool

ToJSON Char

ToJSON Double

ToJSON Float

ToJSON Int

ToJSON Int8

ToJSON Int16

ToJSON Int32

ToJSON Int64

ToJSON Integer

ToJSON Word

ToJSON Word8

ToJSON Word16

ToJSON Word32

ToJSON Word64

ToJSON ()

ToJSON IntSet

ToJSON ZonedTime

ToJSON UTCTime

ToJSON Text

ToJSON Text

ToJSON Value

ToJSON DotNetTime

ToJSON Scientific

ToJSON Number

ToJSON [Char]

ToJSON a => ToJSON [a]

ToJSON (Ratio Integer)

HasResolution a => ToJSON (Fixed a)

ToJSON a => ToJSON (Dual a)

ToJSON a => ToJSON (First a)

ToJSON a => ToJSON (Last a)

ToJSON a => ToJSON (Maybe a)

ToJSON a => ToJSON (IntMap a)

ToJSON a => ToJSON (Set a)

ToJSON v => ToJSON (Tree v)

ToJSON a => ToJSON (Vector a)

(Storable a, ToJSON a) => ToJSON (Vector a)

(Prim a, ToJSON a) => ToJSON (Vector a)

(Vector Vector a, ToJSON a) => ToJSON (Vector a)

ToJSON a => ToJSON (HashSet a)

(ToJSON a, ToJSON b) => ToJSON (Either a b)

(ToJSON a, ToJSON b) => ToJSON (a, b)

ToJSON v => ToJSON (Map String v)

ToJSON v => ToJSON (Map Text v)

ToJSON v => ToJSON (Map Text v)

ToJSON v => ToJSON (HashMap String v)

ToJSON v => ToJSON (HashMap Text v)

ToJSON v => ToJSON (HashMap Text v)

(ToJSON a, ToJSON b, ToJSON c) => ToJSON (a, b, c)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d) => ToJSON (a, b, c, d)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e) => ToJSON (a, b, c, d, e)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f) => ToJSON (a, b, c, d, e, f)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g) => ToJSON (a, b, c, d, e, f, g)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h) => ToJSON (a, b, c, d, e, f, g, h)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i) => ToJSON (a, b, c, d, e, f, g, h, i)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j) => ToJSON (a, b, c, d, e, f, g, h, i, j)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k) => ToJSON (a, b, c, d, e, f, g, h, i, j, k)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l, ToJSON m) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l, m)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l, ToJSON m, ToJSON n) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n)

(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l, ToJSON m, ToJSON n, ToJSON o) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)

class FromJSON a where

Minimal complete definition

Nothing

Methods

parseJSON :: Value -> Parser a

Instances

FromJSON Bool

FromJSON Char

FromJSON Double

FromJSON Float

FromJSON Int

FromJSON Int8

FromJSON Int16

FromJSON Int32

FromJSON Int64

FromJSON Integer

FromJSON Word

FromJSON Word8

FromJSON Word16

FromJSON Word32

FromJSON Word64

FromJSON ()

FromJSON IntSet

FromJSON ZonedTime

FromJSON UTCTime

FromJSON Text

FromJSON Text

FromJSON Value

FromJSON DotNetTime

FromJSON Scientific

FromJSON Number

FromJSON [Char]

FromJSON a => FromJSON [a]

FromJSON (Ratio Integer)

HasResolution a => FromJSON (Fixed a)

FromJSON a => FromJSON (Dual a)

FromJSON a => FromJSON (First a)

FromJSON a => FromJSON (Last a)

FromJSON a => FromJSON (Maybe a)

FromJSON a => FromJSON (IntMap a)

(Ord a, FromJSON a) => FromJSON (Set a)

FromJSON v => FromJSON (Tree v)

FromJSON a => FromJSON (Vector a)

(Storable a, FromJSON a) => FromJSON (Vector a)

(Prim a, FromJSON a) => FromJSON (Vector a)

(Vector Vector a, FromJSON a) => FromJSON (Vector a)

(Eq a, Hashable a, FromJSON a) => FromJSON (HashSet a)

(FromJSON a, FromJSON b) => FromJSON (Either a b)

(FromJSON a, FromJSON b) => FromJSON (a, b)

FromJSON v => FromJSON (Map String v)

FromJSON v => FromJSON (Map Text v)

FromJSON v => FromJSON (Map Text v)

FromJSON v => FromJSON (HashMap String v)

FromJSON v => FromJSON (HashMap Text v)

FromJSON v => FromJSON (HashMap Text v)

(FromJSON a, FromJSON b, FromJSON c) => FromJSON (a, b, c)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSON (a, b, c, d)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e) => FromJSON (a, b, c, d, e)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f) => FromJSON (a, b, c, d, e, f)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g) => FromJSON (a, b, c, d, e, f, g)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h) => FromJSON (a, b, c, d, e, f, g, h)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i) => FromJSON (a, b, c, d, e, f, g, h, i)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j) => FromJSON (a, b, c, d, e, f, g, h, i, j)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k) => FromJSON (a, b, c, d, e, f, g, h, i, j, k)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l, FromJSON m) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l, m)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l, FromJSON m, FromJSON n) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l, FromJSON m, FromJSON n, FromJSON o) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)

Encoding/decoding

encode :: ToJSON a => a -> ByteString

encodeFile :: ToJSON a => FilePath -> a -> IO ()

decode :: FromJSON a => ByteString -> Maybe a

decodeFile :: FromJSON a => FilePath -> IO (Maybe a)

Better error information

decodeEither :: FromJSON a => ByteString -> Either String a

decodeEither' :: FromJSON a => ByteString -> Either ParseException a

More helpful version of decodeEither which returns the YamlException.

Since 0.8.3

decodeFileEither :: FromJSON a => FilePath -> IO (Either ParseException a)

A version of decodeFile which should not throw runtime exceptions.

Since 0.8.4

More control over decoding

decodeHelper :: FromJSON a => Source Parse Event -> IO (Either ParseException (Either String a))