Function

Summary

Invokes an Objective-C method.

Package

objc

Signature

invoke class-or-object-pointer method &rest args => value

Arguments

class-or-object-pointer

A string naming an Objective-C class or a pointer to an Objective-C foreign object.

method

A string naming the method to invoke.

args

Arguments to the method.

Values

value

The value returned by the method.

Description

The function invoke is used to call Objective-C instance and class methods. If class-or-object-pointer is a string, then it must name an Objective-C class and the class method named method in that class is called. Otherwise class-or-object-pointer should be a foreign pointer to an Objective-C object or class and the appropriate instance or class method named method is invoked. The value of method should be a concatenation of the message name and its argument names, including the colons, for example "setWidth:height:" .

Each argument in args is converted to an appropriate FLI Objective-C value and is passed in order to the method. This conversion is done based on the signature of the method as follows:

NSRect

If the argument is a vector of four elements of the form #( x y width height ) , the x , y , width and height are used to form the rectangle. Otherwise it is assumed to be a foreign pointer to a ns-rect nd is copied.

NSSize

If the argument is a vector of two elements of the form #( width height ) , the width and height are used to form the size. Otherwise it is assumed to be a foreign pointer to a ns-size and is copied.

NSPoint

If the argument is a vector of two elements of the form #( x y ) , the x and y are used to form the point. Otherwise it is assumed to be a foreign pointer to a ns-point and is copied.

NSRange

If the argument is a cons of the form ( location . length ) , the location and length are used to form the range. Otherwise it is assumed to be a foreign pointer to a ns-range object and is copied.

other structures

The argument should be a foreign pointer to the appropriate struct object and is copied.

BOOL

If the argument is nil then NO is passed, if the argument is t then YES is passed. Otherwise the argument must be an integer (due to a limitation in the Objective-C type system, this case cannot be distinguished from the signed char type).

id

If the argument is a string then it is converted to a newly allocated Objective-C NSString object which is released when the function returns.

If the argument is a vector then it is recursively converted to a newly allocated Objective-C NSArray object which is released when the function returns.

If the argument is nil then a null pointer is passed.

Otherwise the argument should be a foreign pointer to an Objective-C object of the appropriate class.

Class

The argument is coerced to an Objective-C class pointer as if by coerce-to-objc-class. In particular, this allows strings to be passed as class arguments.

char *

If the argument is a string then it is converted to a newly allocated foreign string which is freed when the function returns.

Otherwise the argument should be a foreign pointer.

struct structname *

The argument should be a foreign pointer to a struct whose type is defined by define-objc-struct with :foreign-name structname .

other integer and pointer types

All other integer and pointer types are converted using the normal FLI rules.

When the method returns, its value is converted according to its type:

NSRect

A vector of four elements of the form #( x y width height ) is created containing the rectangle.

NSSize

A vector of two elements of the form #( width height ) is created containing the size.

NSPoint

A vector of two elements of the form #( x y ) is created containing the point.

NSRange

A cons of the form ( location . length ) is created containing the range.

other structures

Other structures cannot be returned by value using invoke. See invoke-into for how to handle these types.

BOOL

If the value is NO then 0 is returned, otherwise 1 is returned. See also invoke-bool.

id

An object of type objc-object-pointer is returned.

char *

The value is converted to a string and returned.

other integer and pointer types

All other integer and pointer types are converted using the normal FLI rules.

See also

invoke-bool
invoke-into
can-invoke-p