C++ methods are generic functions in the :cxx package.
The C++ method call: myInstance->frob(1); is in Lisp:
(frob my-instance 1)
C++ style overload resolution with conversion sequences is supported. For example this:
(cxx:set-pen (make-instance 'qt:painter) (make-instance 'qt:color:args '("green")))
is equivalent to:
(cxx:set-pen (make-instance 'qt:painter) "green")
In the second case a temporary qt:color instance is implicitly created.
Instead of calling a setter method that takes no additional arguments,
(cxx:set-object-name (make-instance 'qt:object) "foo")
you can use its setfable getter.
(setf (cxx:object-name (make-instance 'qt:object)) "foo")
You can extend the :cxx generic functions by
adding methods. :around, :before, :after
and (call-next-method) are supported.
(defclass the-object-does-nothing (qt:object) () (:metaclasscxx:class)) (defmethod cxx:timer-event ((object the-object-does-nothing) event) (declare (ignore object event)) (call-next-method))
:cxx generic functions can be overload by argument count. Lambda list
keywords (e.g.: &rest and &key) are not supported.
Make sure you have the right number of arguments when adding a method; otherwise it will not be called.
The arguments of the method might have dynamic extend; i.e.: they are only valid in the body of the method.
Unwinding of the C++ stack is not supported. This means that you must not invoke a restart that skips any foreign function.
You will most likely encounter this problem when an error is signaled in a virtual method you have overwritten.
[3]. For this case restarts are provide that allow to return a value for the failed method,
call the default C++ implementation instead (something like #'call-next-method) or retry.
Instead of using the various cxx:operator methods you can use their Lisp equivalent
in the :cxx package.
cxx:> | cxx:>= |
cxx:= | cxx:/= |
cxx:<= | cxx:< |
cxx:+ | cxx:- | cxx:* | cxx:/ |
cxx:1+ | cxx:1- |
cxx:incf | cxx:decf |
cxx:aref |