[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.
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 [method get_method].
[codeblock]
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.
Returns a copy of this [Callable] with one or more arguments bound. When called, the bound arguments are passed [i]after[/i] the arguments supplied by [method call]. See also [method unbind].
[b]Note:[/b] When this method is chained with other similar methods, the order in which the argument list is modified is read from right to left.
Returns a copy of this [Callable] with one or more arguments bound, reading them from an array. When called, the bound arguments are passed [i]after[/i] the arguments supplied by [method call]. See also [method unbind].
[b]Note:[/b] When this method is chained with other similar methods, the order in which the argument list is modified is read from right to left.
Calls the method represented by this [Callable] in deferred mode, i.e. during the idle frame. Arguments can be passed and should match the method's signature.
Calls the method represented by this [Callable]. Unlike [method call], this method expects all arguments to be contained inside the [param arguments] [Array].
Return the bound arguments (as long as [method get_bound_arguments_count] is greater than zero), or empty (if [method get_bound_arguments_count] is less than or equal to zero).
Returns the total amount of arguments bound (or unbound) via successive [method bind] or [method unbind] calls. If the amount of arguments unbound is greater than the ones bound, this function returns a value less than zero.
Returns the 32-bit hash value of this [Callable]'s object.
[b]Note:[/b] [Callable]s with equal content will always produce identical hash values. However, the reverse is not true. Returning identical hash values does [i]not[/i] imply the callables are equal, because different callables can have identical hash values due to hash collisions. The engine uses a 32-bit hash algorithm for [method hash].
Returns [code]true[/code] if this [Callable] is a custom callable. Custom callables are created from [method bind] or [method unbind]. In GDScript, lambda functions are also custom callables.
Returns [code]true[/code] if this [Callable] is a standard callable. This method is the opposite of [method is_custom]. Returns [code]false[/code] if this callable is a lambda function.
Perform an RPC (Remote Procedure Call). This is used for multiplayer and is normally not available, unless the function being called has been marked as [i]RPC[/i]. Calling this method on unsupported functions will result in an error. See [method Node.rpc].
Perform an RPC (Remote Procedure Call) on a specific peer ID (see multiplayer documentation for reference). This is used for multiplayer and is normally not available unless the function being called has been marked as [i]RPC[/i]. Calling this method on unsupported functions will result in an error. See [method Node.rpc_id].
Returns a copy of this [Callable] with a number of arguments unbound. In other words, when the new callable is called the last few arguments supplied by the user are ignored, according to [param argcount]. The remaining arguments are passed to the callable. This allows to use the original callable in a context that attempts to pass more arguments than this callable can handle, e.g. a signal with a fixed number of arguments. See also [method bind].
[b]Note:[/b] When this method is chained with other similar methods, the order in which the argument list is modified is read from right to left.
[codeblock]
func _ready():
foo.unbind(1).call(1, 2) # Calls foo(1).
foo.bind(3, 4).unbind(1).call(1, 2) # Calls foo(1, 3, 4), note that it does not change the arguments from bind.
