[armedbear-devel] Additional slots in function classes screw up std-compute-discriminating-function
Hi,
What the subject says. Here is a test case:
CL-USER(1): (use-package :mop) T CL-USER(2): (defclass my-function (standard-generic-function) ((a-slot :initarg :a-slot :accessor a-slot)) (:metaclass funcallable-standard-class)) #<FUNCALLABLE-STANDARD-CLASS MY-FUNCTION {24DF7EA4}> CL-USER(3): (defgeneric test (x y z) (:generic-function-class my-function)) #<THREAD "interpreter" {14BAAEA8}>: Debugger invoked on condition of type TYPE-ERROR The value TEST is not of type LIST.
The reason is that std-compute-discriminating-function is also called for subclasses of standard-generic-function that don't override compute-discriminating function. The specialization in std-compute-discriminating-function should only occur if the passed function is _extactly_ a standard-generic-function (or if it doesn't add any slots on top of standard-generic-function).
By the way, we're getting closer (ha!). More and more test cases in my test suites work. I'm pretty confident that I can add full support for ABCL in Closer to MOP for the next version of ABCL.
Pascal
-- Pascal Costanza
On Dec 9, 2012, at 17:10, Pascal Costanza pc@p-cos.net wrote:
Hi,
What the subject says. Here is a test case:
CL-USER(1): (use-package :mop) T CL-USER(2): (defclass my-function (standard-generic-function) ((a-slot :initarg :a-slot :accessor a-slot)) (:metaclass funcallable-standard-class)) #<FUNCALLABLE-STANDARD-CLASS MY-FUNCTION {24DF7EA4}> CL-USER(3): (defgeneric test (x y z) (:generic-function-class my-function)) #<THREAD "interpreter" {14BAAEA8}>: Debugger invoked on condition of type TYPE-ERROR The value TEST is not of type LIST.
The reason is that std-compute-discriminating-function is also called for subclasses of standard-generic-function that don't override compute-discriminating function. The specialization in std-compute-discriminating-function should only occur if the passed function is _extactly_ a standard-generic-function (or if it doesn't add any slots on top of standard-generic-function).
Logged at http://trac.common-lisp.net/armedbear/ticket/280, with thanks.
By the way, we're getting closer (ha!). More and more test cases in my test suites work. I'm pretty confident that I can add full support for ABCL in Closer to MOP for the next version of ABCL.
That's great to hear! A maintenance release of ABCL is planned for the beginning of January, I'll try to get in fixes for as many problems as possible.
Rudi
On Dec 9, 2012, at 17:10, Pascal Costanza pc@p-cos.net wrote:
Hi,
What the subject says. Here is a test case:
CL-USER(1): (use-package :mop) T CL-USER(2): (defclass my-function (standard-generic-function) ((a-slot :initarg :a-slot :accessor a-slot)) (:metaclass funcallable-standard-class)) #<FUNCALLABLE-STANDARD-CLASS MY-FUNCTION {24DF7EA4}> CL-USER(3): (defgeneric test (x y z) (:generic-function-class my-function)) #<THREAD "interpreter" {14BAAEA8}>: Debugger invoked on condition of type TYPE-ERROR The value TEST is not of type LIST.
The reason is that std-compute-discriminating-function is also called for subclasses of standard-generic-function that don't override compute-discriminating function. The specialization in std-compute-discriminating-function should only occur if the passed function is _extactly_ a standard-generic-function (or if it doesn't add any slots on top of standard-generic-function).
Thanks - this is hopefully fixed in r14342. I chose to preserve slot order and append slots of child classes at the end, which allows optimized slot access in a number of places.
By the way, we're getting closer (ha!). More and more test cases in my test suites work. I'm pretty confident that I can add full support for ABCL in Closer to MOP for the next version of ABCL.
That's great to hear. I still have to invest a bit of thinking into your other outstanding bug (:default-initargs for generic functions), since that one lives at the intersection of Java, Lisp and the bootstrapping process.
Rudi
armedbear-devel@common-lisp.net
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Pascal Costanza -
Rudolf Schlatte