define-objc-method (
name
result-type
[
result-style
])
(
object-argspec
argspec
*)
form
*
object-argspec ::= ( object-var class-name [ pointer-var ]))
A string naming the method to define.
An Objective-C FLI type.
An optional keyword specifying the result conversion style, either
:lisp
or
:foreign
, or a symbol naming a variable.
A symbol naming a variable.
A symbol naming a class defined with define-objc-class.
An optional symbol naming a variable.
A symbol naming a variable.
An Objective-C FLI type.
An optional symbol or list specifying the argument conversion style.
A form.
The macro
define-objc-method
defines the Objective-C instance method
name
for the Objective-C classes associated with
class-name
. The
name
should be a concatenation of the message name and its argument names, including the colons, for example
"setWidth:height:"
.
If the define-objc-class definition of
class-name
specifies the
(:objc-class-name
objc-class-name
)
option, then the method is added to the Objective-C class
objc-class-name
. Otherwise, the method is added to the Objective-C class of every subclass of
class-name
that specifies the
:objc-class-name
option, allowing a mixin class to define methods that become part of the implementation of its subclasses (see Abstract classes).
When the method is invoked, each form is evaluated in sequence with object-var bound to the object of type class-name associated with the receiver, pointer-var (if specified) bound to the receiver foreign pointer and each arg-var bound to the corresponding method argument.
Each argument has an
arg-type
(its Objective-C FLI type) and an optional
arg-style
, which specifies how the FLI value is converted to a Lisp value. If the
arg-style
is
:foreign
, then the
arg-var
is bound to the FLI value of the argument (typically an integer or foreign pointer). Otherwise, the
arg-var
is bound to a value converted according to the
arg-type
:
If
arg-style
is omitted or
:lisp
then the rectangle is converted to a vector of four elements of the form
#(
x
y
width
height
)
. Otherwise the argument is a foreign pointer to a ns-rect object.
If
arg-style
is omitted or
:lisp
then the size is converted to a vector of two elements of the form
#(
width
height
)
. Otherwise the argument is a foreign pointer to a ns-size object.
If
arg-style
is omitted or
:lisp
then the point is converted to a vector of two elements of the form
#(
x
y
)
. Otherwise the argument is a foreign pointer to a ns-point object.
If
arg-style
is omitted or
:lisp
then the range is converted to a cons of the form
(
location
.
length
)
. Otherwise the argument is a foreign pointer to a ns-range object.
If
arg-style
is the symbol
string
then the argument is assumed to be a pointer to an Objective-C
NSString
object and is converted to a Lisp string or
nil
for a null pointer.
If
arg-style
is the symbol
array
then the argument is assumed to be a pointer to an Objective-C
NSArray
object and is converted to a Lisp vector or
nil
for a null pointer.
If
arg-style
is the a list of the form
(array
elt-arg-style
)
then the argument is assumed to be a pointer to an Objective-C
NSArray
object and is recursively converted to a Lisp vector using
elt-arg-style
for the elements or
nil
for a null pointer.
Otherwise, the argument remains as a foreign pointer to the Objective-C object.
If
arg-style
is the symbol
string
then the argument is assumed to be a pointer to a foreign string and is converted to a Lisp string or
nil
for a null pointer.
After the last form has been evaluated, its value is converted to result-type according to result-style and becomes the result of the method.
If result-style is a non-keyword symbol and the result-type is a foreign structure type defined with define-objc-struct then the variable named by result-style is bound to a pointer to a foreign object of type result-type while the form s are evaluated. The form s must set the slots in this foreign object to specify the result.
If
result-style
is :
foreign
then the value is assumed to be suitable for conversion to
result-type
using the normal FLI rules.
If
result-style
is :
lisp
then additional conversions are performed for specific values of
result-type
:
If the value is a vector of four elements of the form
#(
x
y
width
height
)
, the
x
,
y
,
width
and
height
are used to form the returned rectangle. Otherwise it is assumed to be a foreign pointer to a ns-rect and is copied.
If the value is a vector of two elements of the form
#(
width
height
)
, the
width
and
height
are used to form the returned size. Otherwise it is assumed to be a foreign pointer to a ns-size and is copied.
If the value is a vector of two elements of the form
#(
x
y
)
, the
x
and
y
are used to form the returned point. Otherwise it is assumed to be a foreign pointer to a ns-point and is copied.
If the value is a cons of the form
(
location
.
length
)
, the
location
and
length
are used to form the returned range. Otherwise it is assumed to be a foreign pointer to a ns-range object and is copied.
(:signed :char)
or
(:unsigned :char)
If the value is
nil
then
NO
is returned.If the value is
t
then
YES
is returned. Otherwise the value must be an appropriate integer for
result-type
.
If the value is a string then it is converted to a newly allocated Objective-C
NSString
object which the caller is expected to release.
If the value is a vector then it is recursively converted to a newly allocated Objective-C
NSArray
object which the caller is expected to release.
If the value is
nil
then a null pointer is returned.
Otherwise the value should be a foreign pointer to an Objective-C object of the appropriate class.
The value is coerced to a Objective-C class pointer as if by coerce-to-objc-class. In particular, this allows strings to be returned.
The
form
s can use functions such as invoke to invoke other methods on the
pointer-var
. The macro current-super
can be used to obtain an object that allows methods in the superclass to be invoked (like
super
in Objective-C).