| Safe Haskell | None |
|---|---|
| Language | Haskell98 |
Data.GI.Base.GVariant
Contents
Description
This module contains some helper functions for dealing with GVariant
values. The simplest way of dealing with them is by using the
IsGVariant typeclass:
str <- fromGVariant variant :: IO (Maybe Text)
assuming that the variant is expected to contain a string in UTF8 encoding. The code becomes even shorter if the type checker can determine the return type for you:
readStringVariant :: GVariant -> IO Text
readStringVariant variant =
fromGVariant variant >>= \case
Nothing -> error "Variant was not a string"
Just str -> return strAlternatively, you can use manually the gvariantFrom* and gvariantTo* family of functions.
Synopsis
- class IsGVariant a where
- toGVariant :: a -> IO GVariant
- fromGVariant :: GVariant -> IO (Maybe a)
- toGVariantFormatString :: a -> Text
- class Ord a => IsGVariantBasicType a
- noGVariant :: Maybe GVariant
- gvariantGetTypeString :: GVariant -> IO Text
- newtype GVariantSinglet a = GVariantSinglet a
- data GVariantDictEntry key value = GVariantDictEntry key value
- newtype GVariantHandle = GVariantHandle Int32
- data GVariantObjectPath
- newGVariantObjectPath :: Text -> Maybe GVariantObjectPath
- gvariantObjectPathToText :: GVariantObjectPath -> Text
- data GVariantSignature
- newGVariantSignature :: Text -> Maybe GVariantSignature
- gvariantSignatureToText :: GVariantSignature -> Text
- wrapGVariantPtr :: Ptr GVariant -> IO GVariant
- newGVariantFromPtr :: Ptr GVariant -> IO GVariant
- unrefGVariant :: GVariant -> IO ()
- disownGVariant :: GVariant -> IO (Ptr GVariant)
- gvariantToBool :: GVariant -> IO (Maybe Bool)
- gvariantFromBool :: Bool -> IO GVariant
- gvariantToWord8 :: GVariant -> IO (Maybe Word8)
- gvariantFromWord8 :: Word8 -> IO GVariant
- gvariantToInt16 :: GVariant -> IO (Maybe Int16)
- gvariantFromInt16 :: Int16 -> IO GVariant
- gvariantToWord16 :: GVariant -> IO (Maybe Word16)
- gvariantFromWord16 :: Word16 -> IO GVariant
- gvariantToInt32 :: GVariant -> IO (Maybe Int32)
- gvariantFromInt32 :: Int32 -> IO GVariant
- gvariantToWord32 :: GVariant -> IO (Maybe Word32)
- gvariantFromWord32 :: Word32 -> IO GVariant
- gvariantToInt64 :: GVariant -> IO (Maybe Int64)
- gvariantFromInt64 :: Int64 -> IO GVariant
- gvariantToWord64 :: GVariant -> IO (Maybe Word64)
- gvariantFromWord64 :: Word64 -> IO GVariant
- gvariantToHandle :: GVariant -> IO (Maybe Int32)
- gvariantFromHandle :: Int32 -> IO GVariant
- gvariantToDouble :: GVariant -> IO (Maybe Double)
- gvariantFromDouble :: Double -> IO GVariant
- gvariantToText :: GVariant -> IO (Maybe Text)
- gvariantFromText :: Text -> IO GVariant
- gvariantToObjectPath :: GVariant -> IO (Maybe Text)
- gvariantFromObjectPath :: GVariantObjectPath -> IO GVariant
- gvariantToSignature :: GVariant -> IO (Maybe Text)
- gvariantFromSignature :: GVariantSignature -> IO GVariant
- gvariantToGVariant :: GVariant -> IO (Maybe GVariant)
- gvariantFromGVariant :: GVariant -> IO GVariant
- gvariantToBytestring :: GVariant -> IO (Maybe ByteString)
- gvariantFromBytestring :: ByteString -> IO GVariant
- gvariantFromMaybe :: forall a. IsGVariant a => Maybe a -> IO GVariant
- gvariantToMaybe :: forall a. IsGVariant a => GVariant -> IO (Maybe (Maybe a))
- gvariantFromDictEntry :: (IsGVariant key, IsGVariantBasicType key, IsGVariant value) => key -> value -> IO GVariant
- gvariantToDictEntry :: forall key value. (IsGVariant key, IsGVariantBasicType key, IsGVariant value) => GVariant -> IO (Maybe (key, value))
- gvariantFromMap :: (IsGVariant key, IsGVariantBasicType key, IsGVariant value) => Map key value -> IO GVariant
- gvariantToMap :: forall key value. (IsGVariant key, IsGVariantBasicType key, IsGVariant value) => GVariant -> IO (Maybe (Map key value))
- gvariantFromList :: forall a. IsGVariant a => [a] -> IO GVariant
- gvariantToList :: forall a. IsGVariant a => GVariant -> IO (Maybe [a])
- gvariantFromTuple :: [GVariant] -> IO GVariant
- gvariantToTuple :: GVariant -> IO (Maybe [GVariant])
Documentation
class IsGVariant a where Source #
The typeclass for types that can be automatically marshalled into
GVariant using toGVariant and fromGVariant.
Methods
toGVariant :: a -> IO GVariant Source #
Convert a value of the given type into a GVariant.
fromGVariant :: GVariant -> IO (Maybe a) Source #
Try to decode a GVariant into a target type. If the
conversion fails we return Nothing. The type that was
expected can be obtained by calling toGVariantFormatString,
and the actual type as understood by the GVariant code can be
obtained by calling gvariantToTypeString.
toGVariantFormatString :: a -> Text Source #
The expected format string for this type (the argument is ignored).
Instances
class Ord a => IsGVariantBasicType a Source #
The typeclass for basic type GVariant types, i.e. those that
are not containers.
Instances
| IsGVariantBasicType Bool Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType Double Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType Int16 Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType Int32 Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType Int64 Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType Word8 Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType Word16 Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType Word32 Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType Word64 Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType Text Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType GVariantSignature Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType GVariantObjectPath Source # | |
Defined in Data.GI.Base.GVariant | |
| IsGVariantBasicType GVariantHandle Source # | |
Defined in Data.GI.Base.GVariant | |
noGVariant :: Maybe GVariant Source #
An alias for Nothing :: Maybe GVariant to save some typing.
gvariantGetTypeString :: GVariant -> IO Text Source #
Get the expected type of a GVariant, in GVariant
notation. See
https://developer.gnome.org/glib/stable/glib-GVariantType.html
for the meaning of the resulting format string.
Type wrappers
Some GVariant types are isomorphic to Haskell types, but they
carry some extra information. For example, there is a tuple
singlet type, which is isomorphic to a single Haskell value
with the added bit of information that it is wrapped in a tuple
container. In order to use these values you can use the
following wrappers, which allow the IsGVariant instance to
disambiguate the requested type properly.
newtype GVariantSinglet a Source #
Haskell has no notion of one element tuples, but GVariants do, so
the following allows for marshalling one element tuples properly
using fromGVariant and toGVariant. For instance, to construct a
single element tuple containing a string, you could do
toGVariant (GVariantSinglet "Test")
Constructors
| GVariantSinglet a |
Instances
| Eq a => Eq (GVariantSinglet a) Source # | |
Defined in Data.GI.Base.GVariant Methods (==) :: GVariantSinglet a -> GVariantSinglet a -> Bool # (/=) :: GVariantSinglet a -> GVariantSinglet a -> Bool # | |
| Show a => Show (GVariantSinglet a) Source # | |
Defined in Data.GI.Base.GVariant Methods showsPrec :: Int -> GVariantSinglet a -> ShowS # show :: GVariantSinglet a -> String # showList :: [GVariantSinglet a] -> ShowS # | |
| IsGVariant a => IsGVariant (GVariantSinglet a) Source # | One element tuples. |
Defined in Data.GI.Base.GVariant Methods toGVariant :: GVariantSinglet a -> IO GVariant Source # fromGVariant :: GVariant -> IO (Maybe (GVariantSinglet a)) Source # toGVariantFormatString :: GVariantSinglet a -> Text Source # | |
data GVariantDictEntry key value Source #
A DictEntry GVariant is isomorphic to a two-tuple. Wrapping the
values into a GVariantDictentry allows the IsGVariant instance
to do the right thing.
Constructors
| GVariantDictEntry key value |
Instances
| (Eq key, Eq value) => Eq (GVariantDictEntry key value) Source # | |
Defined in Data.GI.Base.GVariant Methods (==) :: GVariantDictEntry key value -> GVariantDictEntry key value -> Bool # (/=) :: GVariantDictEntry key value -> GVariantDictEntry key value -> Bool # | |
| (Show key, Show value) => Show (GVariantDictEntry key value) Source # | |
Defined in Data.GI.Base.GVariant Methods showsPrec :: Int -> GVariantDictEntry key value -> ShowS # show :: GVariantDictEntry key value -> String # showList :: [GVariantDictEntry key value] -> ShowS # | |
| (IsGVariant a, IsGVariantBasicType a, IsGVariant b) => IsGVariant (GVariantDictEntry a b) Source # | |
Defined in Data.GI.Base.GVariant Methods toGVariant :: GVariantDictEntry a b -> IO GVariant Source # fromGVariant :: GVariant -> IO (Maybe (GVariantDictEntry a b)) Source # toGVariantFormatString :: GVariantDictEntry a b -> Text Source # | |
newtype GVariantHandle Source #
Constructors
| GVariantHandle Int32 |
Instances
data GVariantObjectPath Source #
An object representing a DBus object path, which is a particular
type of GVariant too. (Just a string with some specific
requirements.) In order to construct/deconstruct a
GVariantObjectPath one can use newGVariantObjectPath
and gvariantObjectPathToText.
Instances
newGVariantObjectPath :: Text -> Maybe GVariantObjectPath Source #
Try to construct a DBus object path. If the passed string is not
a valid object path Nothing will be returned.
gvariantObjectPathToText :: GVariantObjectPath -> Text Source #
Return the Text representation of a GVariantObjectPath.
data GVariantSignature Source #
An object representing a DBus signature, which is a particular
type of GVariant too. (Just a string with some specific
requirements.) In order to construct/deconstruct a
GVariantSignature one can use newGVariantSignature and
gvariantSignatureToText.
Instances
newGVariantSignature :: Text -> Maybe GVariantSignature Source #
Try to construct a DBus object path. If the passed string is not
a valid DBus signature Nothing will be returned.
gvariantSignatureToText :: GVariantSignature -> Text Source #
Return the Text representation of a GVariantSignature.
Manual memory management
wrapGVariantPtr :: Ptr GVariant -> IO GVariant Source #
Take ownership of a passed in Ptr (typically created just for
us, so if it is floating we sink it).
newGVariantFromPtr :: Ptr GVariant -> IO GVariant Source #
Construct a Haskell wrapper for the given GVariant, without
assuming ownership.
disownGVariant :: GVariant -> IO (Ptr GVariant) Source #
Disown a GVariant, i.e. do not unref the underlying object when
the Haskell object is garbage collected.
Manual conversions
Basic types
The use of these should be fairly self-explanatory. If you
want to convert a Haskell type into a GVariant, use
gvariantTo*. If you want to convert a GVariant into a Haskell
type, use gvariantFrom*. The conversion can fail if the
GVariant is not of the expected type (if you want to convert
a GVariant containing a Int16 into a Text value, say), in
which case Nothing will be returned.
gvariantToObjectPath :: GVariant -> IO (Maybe Text) Source #
Extract a GVariantObjectPath from a GVariant, represented as
its underlying Text representation.
gvariantFromObjectPath :: GVariantObjectPath -> IO GVariant Source #
Construct a GVariant containing an object path. In order to
build a GVariantObjectPath value see newGVariantObjectPath.
gvariantToSignature :: GVariant -> IO (Maybe Text) Source #
Extract a GVariantSignature from a GVariant, represented as
Text.
gvariantFromSignature :: GVariantSignature -> IO GVariant Source #
Construct a GVariant containing an DBus signature. In order to
build a GVariantSignature value see newGVariantSignature.
Container type conversions
gvariantToBytestring :: GVariant -> IO (Maybe ByteString) Source #
Extract a zero terminated list of bytes into a ByteString.
gvariantFromBytestring :: ByteString -> IO GVariant Source #
Encode a ByteString into a list of bytes GVariant.
gvariantFromMaybe :: forall a. IsGVariant a => Maybe a -> IO GVariant Source #
gvariantToMaybe :: forall a. IsGVariant a => GVariant -> IO (Maybe (Maybe a)) Source #
gvariantFromDictEntry :: (IsGVariant key, IsGVariantBasicType key, IsGVariant value) => key -> value -> IO GVariant Source #
Construct a GVariant of type DictEntry from the given key and
value. The key must be a basic GVariant type, i.e. not a
container. This is determined by whether it belongs to the
IsGVariantBasicType typeclass. On the other hand value is an
arbitrary GVariant, and in particular it can be a container type.
gvariantToDictEntry :: forall key value. (IsGVariant key, IsGVariantBasicType key, IsGVariant value) => GVariant -> IO (Maybe (key, value)) Source #
Unpack a DictEntry variant into key and value, which are
returned as a two element tuple in case of success.
gvariantFromMap :: (IsGVariant key, IsGVariantBasicType key, IsGVariant value) => Map key value -> IO GVariant Source #
Pack a Map into a GVariant for dictionary type, which is just
an array of GVariantDictEntry.
gvariantToMap :: forall key value. (IsGVariant key, IsGVariantBasicType key, IsGVariant value) => GVariant -> IO (Maybe (Map key value)) Source #
Unpack a GVariant into a Map. Notice that this assumes that
all the elements in the GVariant array of GVariantDictEntry are
of the same type, which is not necessary for a generic GVariant,
so this is somewhat restrictive. For the general case it is
necessary to use gvariantToList plus gvariantToDictEntry
directly.
gvariantFromList :: forall a. IsGVariant a => [a] -> IO GVariant Source #
Given a list of elements construct a GVariant array containing
them.
gvariantToList :: forall a. IsGVariant a => GVariant -> IO (Maybe [a]) Source #
Unpack a GVariant array into its elements.