Welcome to Affinity!
WARNING: This is still a WIP project. It can still be broken and API can change heavily.
Affinity is a higher layer of abstraction over CFFI. It tries to make the writing of bindings easier. Specifically, Affinity prioritize the next features in decreasing order:
- Ease of use.
- Power.
- Efficiency.
Manually for now.
cd ~/common-lisp
git clone https://github.com/HectareaGalbis/Affinity.git;; A function called foo.
(affi:defcfun (foo "Foo") :int ((str :string-ptr) (b :bool))
"Do cool stuff.")
;; Another function to set callbacks.
(affi:defcfun (set-callback "SetCallback") ((func (:function :int (arg1 :string-ptr) (arg2 :bool))))
"Sets a callback.")
;; A callback definer.
(affi:define-callback-definer define-bar-callback :int (arg1 :string-ptr) (arg2 :bool))
;; A callback named foo2
(define-bar-callback foo2 (str b)
;; Do something cool and return an integer
)
;; Set foo and foo2 as callbacks
(set-callback #'foo)
(set-callback #'foo2)
;; Call foo and foo2
(foo "Hey" t)
(foo2 "This works too!" nil)
;; Defining another function with the extended version
(affi:define-c-function get-size (err-code :int)
((w (:pointer :int) :private t :with (affi:foreign-alloc :int)) ; Stack allocated int (yes, stack)
(h (:pointer :int) :private t :with (affi:foreign-alloc :int))) ; Stack allocated int (yes, stack)
(declare (ignore err-code))
(values (affi:mem-ref w) (affi:mem-ref h)))
(multiple-value-bind (w h) (get-size)
;; Do something with the size
)(affi:defcstruct foo
(str (:string-array 100) :with "This is the default value of str.")
(elements (:list-ptr :float size)) ; The type uses size slot
(size :size :private t)) ; The size slot is private
(let ((lisp-foo (make-foo :elements '(1.5 2.6 3.7)))) ;; A regular list object
(with-slots (str elements) lisp-foo
;; (slot-value lisp-foo 'size) <- Error, size is private
(print str))) ; -> "This is the default value of str."
(affi:with-foreign-object (ptr-foo (:struct foo)) ; Stack allocated foreign structure
(with-slots (str elements) ptr-foo ; Same syntax as regular lisp objects
;; (slot-value lisp-foo 'size) <- Error, size is private
(print str) ; -> "This is the default value of str."
(setf elements '(1.0 2.0 3.0)))) ; The size slot is set automatically to 3.
; The allocated memory is also freed automatically.
; But not be scared, you have total control over memory management.