Interfacing Raku to Gnome GTK+


An action interface


Gnome::Gio::Action represents a single named action.

The main interface to an action is that it can be activated with activate(). This results in the ‘activate’ signal being emitted.

An action may optionally have a state, in which case the state may be set with change-state(). This call takes a N-GObject. The correct type for the state is determined by a static state type (which is given at construction time).

The state may have a hint associated with it, specifying its valid range.

Gnome::Gio::Action is merely the interface to the concept of an action, as described above. Various implementations of actions exist, including GSimpleAction.

In all cases, the implementing class is responsible for storing the name of the action, the parameter type, the enabled state, the optional state type and the state and emitting the appropriate signals when these change. The implementor is responsible for filtering calls to activate() and change-state() for type safety and for the state being enabled.

Probably the only useful thing to do with a Gnome::Gio::Action is to put it inside of a GSimpleActionGroup.



unit role Gnome::Gio::Action;



Activates the action. $parameter must be the correct type of parameter for the action (ie: the parameter type given at construction time). If the parameter type was undefined then $parameter must also be undefined. If the $parameter GVariant is floating, it is consumed.

method activate ( N-GObject $parameter )
  • N-GObject $parameter; the parameter to the activation


Request for the state of this action to be changed to $value. The action must be stateful and value must be of the correct type. See get-state-type(). This call merely requests a change. The action may refuse to change its state or may change its state to something other than value. See get-state-hint().

method change-state ( N-GObject $value )
  • N-GObject $value; the new state


Checks if this action is currently enabled. An action must be enabled in order to be activated or in order to have its state changed from outside callers.

Returns: whether the action is enabled

method get-enabled ( --> Bool )


Queries the name of this action.

Returns: the name of the action.

method get-name ( -->  Str  )


Queries the type of the parameter that must be given when activating this action. When activating the action using activate(), the N-GObject given to that function must be of the type returned by this function. In the case that this function returns undefined, you must not give any N-GObject, but undefined instead.

Returns: the parameter type.

method get-parameter-type ( --> Gnome::Glib::VariantType )


Queries the current state of this action. If the action is not stateful then undefined will be returned. If the action is stateful then the type of the return value is the type given by get-state-type(). The return value (if not undefined) should be freed with clear-object() when it is no longer required.

Returns: the current state of the action.

method get-state ( --> Gnome::Glib::Variant )


Requests a hint about the valid range of values for the state of this action. If an undefined value is returned, it either means that the action is not stateful or that there is no hint about the valid range of values for the state of the action.

Returns: the state range hint, an undefined, array or tuple Variant.

method get-state-hint ( --> Gnome::Glib::Variant )


Queries the type of the state of this action. If the action is stateful, then this function returns the Gnome::Glib::VariantType of the state. This is the type of the initial value given as the state. All calls to change-state() must give a N-GObject of this type and get-state() will return a N-GObject of the same type. If the action is not stateful, then this function will return an undefined type. In that case, get-state() will return undefined and you must not call change-state().

Returns: the state type, if the action is stateful

method get-state-type ( --> Gnome::Glib::VariantType )


Checks if $action_name is valid. $action_name is valid if it consists only of alphanumeric characters, plus ‘-‘ and ‘.’. The empty string is not a valid action name. It is an error to call this function with a non-utf8 action_name.

Returns: True if action_name is valid

method name-is-valid (  Str  $action_name --> Bool )
  • Str $action_name; an potential action name


Parses a detailed action name into its separate name and target components. Detailed action names can have three formats.

The first format is used to represent an action name with no target value and consists of just an action name containing no whitespace or the characters ‘:’, ‘(‘ or ‘)’. For example: app.action.

The second format is used to represent an action with a target value that is a non-empty string consisting only of alphanumerics, plus ‘-‘ and ‘.’. In that case, the action name and target value are separated by a double colon (“::”). For example: app.action::target.

The third format is used to represent an action with any type of target value, including strings. The target value follows the action name, surrounded in parens. For example: app.action(42).

The target value is parsed using parse() from Gnome::Glib::Variant. If a tuple-typed value is desired, it must be specified in the same way, resulting in two sets of parens, for example: app.action((1,2,3)). A string target can be specified this way as well: app.action(‘target’). For strings, this third format must be used if the target value is empty or contains characters other than alphanumerics, ‘-‘ and ‘.’.

Returns: A List

method parse-detailed-name ( Str $detailed_name --> List )
  • Str $detailed_name; a detailed action name

The returned List contains;

  • Str $action_name; the action name

  • Gnome::Glib::Variant $target_value; the target value, or an undefined type for no target

  • Gnome::Glib::Error which is invalid if call returns successfull or is valid with an error message and code explaining the cause.

Formats a detailed action name from $action_name and $target_value. It is an error to call this function with an invalid action name. This function is the opposite of parse-detailed-name(). It will produce a string that can be parsed back to the $action_name and $target_value by that function. See that function for the types of strings that will be printed by this function.

Returns: a detailed format string

method print-detailed-name (
  Str $action_name, N-GObject $target_value
  --> Str
  • Str $action_name; a valid action name

  • N-GObject $target_value; a N-GObject target value, or undefined


An example of using a string type property of a Gnome::Gtk3::Label object. This is just showing how to set/read a property, not that it is the best way to do it. This is because a) The class initialization often provides some options to set some of the properties and b) the classes provide many methods to modify just those properties. In the case below one can use new(:label(‘my text label’)) or gtk_label_set_text(‘my text label’).

my Gnome::Gtk3::Label $label .= new;
my Gnome::GObject::Value $gv .= new(:init(G_TYPE_STRING));
$label.g-object-get-property( 'label', $gv);
$gv.g-value-set-string('my text label');

Supported properties

Action Name

The name of the action. This is mostly meaningful for identifying the action once it has been added to a GActionGroup. It is immutable.

The Gnome::GObject::Value type of property name is G_TYPE_STRING.

Parameter Type

The type of the parameter that must be given when activating the action. This is immutable, and may be Any if no parameter is needed when activating the action.

The Gnome::GObject::Value type of property parameter-type is G_TYPE_BOXED.


If this action is currently enabled.

If the action is disabled then calls to g_action_activate() and g_action_change_state() have no effect.

The Gnome::GObject::Value type of property enabled is G_TYPE_BOOLEAN.

State Type

The N-GObject of the state that the action has, or Any if the action is stateless. This is immutable.

The Gnome::GObject::Value type of property state-type is G_TYPE_BOXED.


The state of the action, or Any if the action is stateless.

The Gnome::GObject::Value type of property state is G_TYPE_VARIANT.