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Callable¶

A built-in type representing a method or a standalone function.

Description¶

Callable is a built-in Variant type that represents a function. It can either be a method within an Object instance, or a standalone function not related to any object, like a lambda function. Like all Variant types, it can be stored in variables and passed to other functions. It is most commonly used for signal callbacks.

Example:

func print_args(arg1, arg2, arg3 = ""):
    prints(arg1, arg2, arg3)

func test():
    var callable = Callable(self, "print_args")
    callable.call("hello", "world")  # Prints "hello world ".
    callable.call(Vector2.UP, 42, callable)  # Prints "(0, -1) 42 Node(node.gd)::print_args".
    callable.call("invalid")  # Invalid call, should have at least 2 arguments.

// Default parameter values are not supported.
public void PrintArgs(Variant arg1, Variant arg2, Variant arg3 = default)
{
    GD.PrintS(arg1, arg2, arg3);
}

public void Test()
{
    // Invalid calls fail silently.
    Callable callable = new Callable(this, MethodName.PrintArgs);
    callable.Call("hello", "world"); // Default parameter values are not supported, should have 3 arguments.
    callable.Call(Vector2.Up, 42, callable); // Prints "(0, -1) 42 Node(Node.cs)::PrintArgs".
    callable.Call("invalid"); // Invalid call, should have 3 arguments.
}

In GDScript, it's possible to create lambda functions within a method. Lambda functions are custom callables that are not associated with an Object instance. Optionally, lambda functions can also be named. The name will be displayed in the debugger, or when calling get_method.

func _init():
    var my_lambda = func (message):
        print(message)

    # Prints Hello everyone!
    my_lambda.call("Hello everyone!")

    # Prints "Attack!", when the button_pressed signal is emitted.
    button_pressed.connect(func(): print("Attack!"))

Note: Methods of native types such as Signal, Array, or Dictionary are not of type Callable in order to avoid unnecessary overhead. If you need to pass those methods as Callable, use a lambda function as a wrapper.

func _init():
    var my_dictionary = { "hello": "world" }

    # This will not work, `clear` is not a callable.
    create_tween().tween_callback(my_dictionary.clear)

    # This will work, as lambdas are custom callables.
    create_tween().tween_callback(func(): my_dictionary.clear())

Note

There are notable differences when using this API with C#. See Différences de l'API C# par rapport à GDScript for more information.

Constructors¶

Callable	Callable ( )
Callable	Callable ( Callable from )
Callable	Callable ( Object object, StringName method )

Methods¶

Callable	bind ( ... ) vararg const
Callable	bindv ( Array arguments )
Variant	call ( ... ) vararg const
void	call_deferred ( ... ) vararg const
Variant	callv ( Array arguments ) const
Array	get_bound_arguments ( ) const
int	get_bound_arguments_count ( ) const
StringName	get_method ( ) const
Object	get_object ( ) const
int	get_object_id ( ) const
int	hash ( ) const
bool	is_custom ( ) const
bool	is_null ( ) const
bool	is_standard ( ) const
bool	is_valid ( ) const
void	rpc ( ... ) vararg const
void	rpc_id ( int peer_id, ... ) vararg const
Callable	unbind ( int argcount ) const

Operators¶

bool	operator != ( Callable right )
bool	operator == ( Callable right )

Constructor Descriptions¶

Callable Callable ( )

Constructs an empty Callable, with no object nor method bound.

Callable Callable ( Callable from )

Constructs a Callable as a copy of the given Callable.

Callable Callable ( Object object, StringName method )

Creates a new Callable for the method named method in the specified object.

Method Descriptions¶

Callable bind ( ... ) vararg const

Returns a copy of this Callable with one or more arguments bound. When called, the bound arguments are passed after the arguments supplied by call. See also unbind.

Note: When this method is chained with other similar methods, the order in which the argument list is modified is read from right to left.

Callable bindv ( Array arguments )

Returns a copy of this Callable with one or more arguments bound, reading them from an array. When called, the bound arguments are passed after the arguments supplied by call. See also unbind.

Note: When this method is chained with other similar methods, the order in which the argument list is modified is read from right to left.

Variant call ( ... ) vararg const

Calls the method represented by this Callable. Arguments can be passed and should match the method's signature.

void call_deferred ( ... ) vararg const

Calls the method represented by this Callable in deferred mode, i.e. at the end of the current frame. Arguments can be passed and should match the method's signature.

func _ready():
    grab_focus.call_deferred()