Data.GI.Base.Signals

Routines for connecting GObjects to signals. There are two basic variants, on and after, which correspond to g_signal_connect and g_signal_connect_after, respectively.

Basic usage is

 on widget #signalName $ do ...

or

 after widget #signalName $ do ...

Note that in the Haskell bindings we represent the signal name in camelCase, so a signal like script-message-received in the original API becomes scriptMessageReceived in the bindings.

There are two variants of note. If you want to provide a detail when connecting the signal you can use :::, as follows:

 on widget (#scriptMessageReceived ::: "handlerName") $ do ...

On the other hand, if you want to connect to the "notify" signal for a property of a widget, it is recommended to use instead PropertyNotify, as follows:

 on widget (PropertyNotify #propertyName) $ do ...

which has the advantage that it will be checked at compile time that the widget does indeed have the property "propertyName".

Documentation

on :: forall object info m. (GObject object, MonadIO m, SignalInfo info) => object -> SignalProxy object info -> ((?self :: object) => HaskellCallbackType info) -> m SignalHandlerId

Connect a signal to a signal handler.

after :: forall object info m. (GObject object, MonadIO m, SignalInfo info) => object -> SignalProxy object info -> ((?self :: object) => HaskellCallbackType info) -> m SignalHandlerId

Connect a signal to a handler, running the handler after the default one.

data SignalProxy (object :: Type) (info :: Type) where

Support for overloaded signal connectors.

Constructors

SignalProxy :: SignalProxy o info

A basic signal name connector.

(:::) :: forall o info. SignalProxy o info -> Text -> SignalProxy o info

A signal connector annotated with a detail.

PropertyNotify :: (info ~ ResolveAttribute propName o, AttrInfo info, pl ~ AttrLabel info, KnownSymbol pl) => AttrLabelProxy propName -> SignalProxy o GObjectNotifySignalInfo

A signal connector for the notify signal on the given property.

Instances

info ~ ResolveSignal slot object => IsLabel slot (SignalProxy object info)

Support for overloaded labels.

Defined in Data.GI.Base.Signals

Methods

fromLabel :: SignalProxy object info

data SignalConnectMode

Whether to connect a handler to a signal with connectSignal so that it runs before/after the default handler for the given signal.

Constructors

SignalConnectBefore

Run before the default handler.

SignalConnectAfter

Run after the default handler.

connectSignalFunPtr :: GObject o => o -> Text -> FunPtr a -> SignalConnectMode -> Maybe Text -> IO SignalHandlerId

Connect a signal to a handler, given as a FunPtr.

disconnectSignalHandler :: GObject o => o -> SignalHandlerId -> IO ()

Disconnect a previously connected signal.

type SignalHandlerId = CULong

Type of a GObject signal handler id.

class SignalInfo (info :: Type) where

Information about an overloaded signal.

Minimal complete definition

connectSignal

Associated Types

type HaskellCallbackType info :: Type

The type for the signal handler.

Methods

connectSignal :: GObject o => o -> (o -> HaskellCallbackType info) -> SignalConnectMode -> Maybe Text -> IO SignalHandlerId

Connect a Haskell function to a signal of the given GObject, specifying whether the handler will be called before or after the default handler. Note that the callback being passed here admits an extra initial parameter with respect to the usual Haskell callback type. This will be passed as an implicit ?self argument to the Haskell callback.

dbgSignalInfo :: Maybe ResolvedSymbolInfo

Optional extra debug information, for resolveSignal below.

Instances

SignalInfo GObjectNotifySignalInfo

Defined in Data.GI.Base.Signals

Associated Types

type HaskellCallbackType GObjectNotifySignalInfo

Methods

connectSignal :: GObject o => o -> (o -> HaskellCallbackType GObjectNotifySignalInfo) -> SignalConnectMode -> Maybe Text -> IO SignalHandlerId

dbgSignalInfo :: Maybe ResolvedSymbolInfo

data GObjectNotifySignalInfo

Connection information for a "notify" signal indicating that a specific property changed (see PropertyNotify for the relevant constructor).

Instances

SignalInfo GObjectNotifySignalInfo

Defined in Data.GI.Base.Signals

Associated Types

type HaskellCallbackType GObjectNotifySignalInfo

Methods

connectSignal :: GObject o => o -> (o -> HaskellCallbackType GObjectNotifySignalInfo) -> SignalConnectMode -> Maybe Text -> IO SignalHandlerId

dbgSignalInfo :: Maybe ResolvedSymbolInfo

type HaskellCallbackType GObjectNotifySignalInfo

Defined in Data.GI.Base.Signals

type HaskellCallbackType GObjectNotifySignalInfo

type family SignalCodeGenError (signalName :: Symbol) :: Type where ...

Generate an informative type error whenever one tries to use a signal for which code generation has failed.

Equations

SignalCodeGenError signalName = TypeError ((('Text "The signal \8216" :<>: 'Text signalName) :<>: 'Text "\8217 is not supported, because haskell-gi failed to generate appropriate bindings.") :$$: 'Text "Please file an issue at https://github.com/haskell-gi/haskell-gi/issues.")

resolveSignal :: forall object info. (GObject object, SignalInfo info) => object -> SignalProxy object info -> Maybe ResolvedSymbolInfo

Return the fully qualified signal name that a given overloaded signal resolves to (mostly useful for debugging).

resolveSignal #childNotify button