So actually
(defun (setf jfield) (newvalue class-ref-or-field field-or-instance &optional ( instance :noinst) unusedvalue) (if (eq instance :noinst) (jfield class-ref-or-field field-or-instance newvalue) (jfield class-ref-or-field field-or-instance instance newvalue)))
Would be a little better.. good eye.
----- Original Message ----- From: dmiles@users.sourceforge.net To: "Alessio Stalla" alessiostalla@gmail.com Cc: "Armed Bear" armedbear-devel@common-lisp.net Sent: Monday, November 23, 2009 6:27 AM Subject: Re: [armedbear-devel] SETF for JFEILDS
----- Original Message ----- From: "Alessio Stalla" alessiostalla@gmail.com To: dmiles@users.sourceforge.net Cc: "Armed Bear" armedbear-devel@common-lisp.net Sent: Monday, November 23, 2009 5:42 AM Subject: Re: [armedbear-devel] SETF for JFEILDS
On Mon, Nov 23, 2009 at 2:36 PM, logicmoo@gmail.com wrote:
Does anyone object to adding this to java.lisp? If not could it be done?
(defun (setf jfield) (newvalue class-ref-or-field field-or-instance &optional ( instance :noinst) (value :novalue)) (if (eq instance :noinst) (jfield class-ref-or-field field-or-instance newvalue) (jfield class-ref-or-field field-or-instance instance newvalue)))
It seems a nice idea to me, but there are a couple of things that I don't understand:
A>- why :noinst and not simply nil?
JFIELD is defined as: class-ref-or-field field-or-instance &optional instance value The valid argument patterns for this operation are: (class-ref field-name): to retrieve the value of a static field. (class-ref field-name instance-ref): to retrieve the value of a class field of the instance. (class-ref field-name primitive-value:) to store primitive-value in a static field. (class-ref field-name instance-ref value): to store value in a class field of the instance. (class-ref field-name nil value): to store value in a static field (when value may be confused with an instance-ref). (field-name instance): to retrieve the value of a field of the instance. The class is derived from the instance. (field-name instance value): to store value in a field of the instance. The class is derived from the instance.
JFIELD doesn't distingusih between static and non static fields
Also cases of "class-ref field-name instance-ref value" (accessing superclass field)
Depending on how the field is defined
(setf (jfield *MyClass* "someStaticBooleanField") NIL) it is distinguable from (setf (jfield *MySuperClass* "nonStaticBooleanField" *my-instance* ) NIL)
A>- value is not used, what's the point of it?
correct the "default :novalue" is not needed. (I was debugging and trying to find corner cases with all those bizzare legal jfield signatures )
but... "value" as an &optional was needed to match the signature of what is legal for jfield so things like this can work:
(define-symbol-macro %iscold (jfield "org.armedbear.lisp.Lisp" "cold")) %iscold ;; ==> NIL (setq %iscold T) ;; ==> T %iscold ;; ==> T (setq %iscold NIL) ;; ==> NIL