January 2011 - armedbear-devel - mailman3.common-lisp.net

[armedbear-devel] json-rpc?
by Axel Rauschmayer 27 Apr '11

27 Apr '11

I think ABCL would make an excellent Ajax server. As such, it would have to support json-rpc. Any suggestions as to how to make this happen? The first part is obviously the server, where the two choices that I can see are Hunchentoot and a servlet container such as Tomcat. In the latter case, I would expect to use a technique like abcl-web (which seems a little bit complicated, but doable). The second part is the JSON parsing. How would I do that? Via CL-JSON? Via Yason? Via a Java library? Sorry for these newbie questions. I’m just getting started with Common Lisp and ABCL. Thanks, Axel -- Axel.Rauschmayer(a)ifi.lmu.de http://www.pst.ifi.lmu.de/~rauschma/

4 10

[armedbear-devel] :case :common
by pjb＠informatimago.com 27 Feb '11

27 Feb '11

CLHS says: 19.2.2.1.2.2 Common Case in Pathname Components For the functions in Figure 19-2, a value of :common for the :case argument that these functions should receive and yield strings in component values according to the following conventions: * All uppercase means to use a file system's customary case. * All lowercase means to use the opposite of the customary case. * Mixed case represents itself. Note that these conventions have been chosen in such a way that translation from :local to :common and back to :local is information-preserving. [pjb@kuiper :0.0 lisp]$ abcl Armed Bear Common Lisp 0.20.0 Java 1.6.0_22 Sun Microsystems Inc. Java HotSpot(TM) Server VM Low-level initialization completed in 0.265 seconds. Startup completed in 0.718 seconds. Type ":help" for a list of available commands. CL-USER(1): (make-pathname :name "TEST" :type "LISP" :case :common) #P"TEST.LISP" CL-USER(2): (namestring (make-pathname :name "TEST" :type "LISP" :case :common)) "TEST.LISP" I'm on a linux system on a ext3 file system. The customary case is lower case (case significant on this particular file system, but 99.999% of the files on unix are lower case). Therefore I would expect to get #P"test.lisp" Notice that: (make-pathname :name "test" :type "lisp" :case :common) should produce #P"TEST.LISP" and that: (make-pathname :name "Test" :type "Lisp" :case :common) should produce #P"Test.Lisp" And that I understand "yeld strings in component values" to mean that the processing should be done on each parameter independently. -- __Pascal Bourguignon__ http://www.informatimago.com/ A bad day in () is better than a good day in {}.

3 4

[armedbear-devel] Registering Java Exceptions
by William 14 Feb '11

14 Feb '11

Hi, I am trying to register Java exceptions using REGISTER-JAVA-EXCEPTION but it does not seem to work for me as evidenced by the transcript below. Is there anything that I may have missed? Armed Bear Common Lisp 0.23.1 Java 1.6.0_20 Sun Microsystems Inc. Java HotSpot(TM) 64-Bit Server VM Low-level initialization completed in 0.354 seconds. Startup completed in 1.579 seconds. Type ":help" for a list of available commands. CL-USER(1): (define-condition java-illegal-argument-error (java-exception) ()) JAVA-ILLEGAL-ARGUMENT-ERROR CL-USER(2): (register-java-exception "java.lang.IllegalArgumentException" 'java-illegal-argument-error) NIL CL-USER(3): (ignore-errors (jstatic (jmethod "java.lang.String" "valueOf" "int") "java.lang.String" "12")) NIL #<JAVA-EXCEPTION {4A6F19D5}> CL-USER(4): (jstatic (jmethod "java.lang.String" "valueOf" "int") "java.lang.String" "12") #<THREAD "interpreter" {2690ED81}>: Debugger invoked on condition of type JAVA-EXCEPTION #<JAVA-EXCEPTION {74D8C3EE}> Restarts: 0: TOP-LEVEL Return to top level. [1] CL-USER(5): 0 CL-USER(6): Kind regards, Martin.

2 1

[armedbear-devel] couple of difficult to debug clos situations
by Alan Ruttenberg 13 Feb '11

13 Feb '11

(defclass a (b)) (make-instance 'a) ; Evaluation aborted on NIL. ;; no backtrace in slime The problem is that b is not defined, but the error makes this difficult to discern. --- Trying to fix the problem in some ways leads to more: (defclass a1 (b1)) (defclass b2 ()) CL-USER> (make-instance 'a1) ; Evaluation aborted on NIL. ;; no backtrace in slime CL-USER> (defclass a1 (b2)) ; Evaluation aborted on NIL. ;; no backtrace in slime --- (defclass a3 (b3)) (mop::class-prototype (find-class 'a3)) ;; here we get a backtrace: #<STANDARD-CLASS A3 {1E8E471}> is not finalized. However it is hard to figure out what the problem is. Now try to fix it: (defclass b3 ()) (mop::class-prototype (find-class 'a3)) ;; still get "is not finalized" error (make-instance 'a3) ;; succeeds (mop::class-prototype (find-class 'a3)) ;; now it succeeds -Alan

2 1

[armedbear-devel] (defstruct (teststruct (:type list) :named) testslot)))
by Alan Ruttenberg 03 Feb '11

03 Feb '11

(defstruct (teststruct (:type list) :named) testslot))) causes the following defun to be compiled: (DEFUN NIL (SYSTEM::INSTANCE) (ELT SYSTEM::INSTANCE 0)) That shouldn't be. Particularly if (fdefinition nil) gives an error. -Alan

2 2

[armedbear-devel] [RFC] How to better support disposal of class objects
by Erik Huelsmann 31 Jan '11

31 Jan '11

To prevent any confusion beforehand: The mail below talks about class objects, objects which store class definitions, not the actual instances of those classes, which use those class definitions and store class-allocated or instance values. We have fixed a few bugs where memory would be allocated during (package creation or) FASL loading, but would not be freed upon package deletion. That was an issue because it's an explicit use-case for Blake. Last weekend I came up with another "leak" in ABCL. The word "leak" is between quotes, because depending on how you look at it, not all of it may technically be leaky. My point: it's easy to create a class; simply use a DEFCLASS form. However, unlike package creation, which can be "undone" through DELETE-PACKAGE, there's no DELETE-CLASS function to undo the result of a DEFCLASS. I started to think about supporting the use-case of deleting a class. Digging around in our implementation, I found there are several reasons why a class won't be automatically cleaned up when the package containing its naming symbol is deleted: 1. Every parent maintains a list of subclasses The list contains class objects, meaning that the actual class-object is referenced in this list and for that reason can't be GC-ed 2. Every generic function maintains a list of specializing methods The methods in the list refer to the dispatch types, meaning that the class-objects are strongly referenced from there too 3. Our FIND-CLASS implementation contains strong references to both the naming symbols as well as the class-objects. 4. Our implementation uses a cache to speed up the calls to generic functions. This cache uses strong references too. The issue in item (3) can be solved (relatively) easy by developing a weak hash table which contains both weak keys and values. This hash table could even be made available as regular Lisp objects. Item (4) currently uses an explicitly specialized hash table implemented on the Java side. The hash table could be adapted to use weak references as well - the effort wouldn't be as generally usable, but that's just tough luck. Items (1) and (2) are something to think about though: Is it wise to implement a function which removes the methods and the class from its parent? What if the class itself has direct subclasses? Do we signal an error? Do we provide a parameter forcing the deletion of a whole tree? Or maybe we should just document how potential users of our CLOS should proceed if they have the intention to do this, since it won't be portable anyway? Myself, I'm currently contemplating "just document" on one hand and "do whatever we can, even if they're whole trees" on the other... What do other people think? Bye, Erik.

2 2

[armedbear-devel] Start up message suggestion
by Blake McBride 31 Jan '11

31 Jan '11

Greetings, I've got a suggestion regarding the startup message on development versions of abcl. Rather that just saying "-dev" why don't we say "-dev (XXX)" where XXX is the subversion revision number? This would make it much more clear about what you are running, and I'm pretty sure subversion can automatically provide and update this (I am doing it elsewhere). Thanks. Blake McBride

6 12

[armedbear-devel] ext:run-shell-program
by Alex Mizrahi 30 Jan '11

30 Jan '11

hi I'd like to recieve output of external program as a stream, i.e. without getting it all in one (potentially) huge string but processing it in small portions as it comes. But it looks like this is not possible to do this with ext:run-shell-program -- it accepts output stream as parameter, but I can't read from output stream, and there is no way to translate output stream into input string in CL. (make-echo-stream does the opposite.) So ... am I missing something? If not, what is the best way to implement this?

1 0

[armedbear-devel] Thanks for the error message fix
by Blake McBride 26 Jan '11

26 Jan '11

Greetings, Thanks a lot for fixed the error messages. I can't tell you how much easier debugging has been. Thanks! Blake McBride

1 0

[armedbear-devel] Filename errors in Windows
by Arie van Wingerden 26 Jan '11

26 Jan '11

Hi, I just started with ABCL using the J editor on WinXP SP3. I replaced the ABCL jar in the J lib with the latest 0.23.1, but also in the old version ABCL 0.19 I had the same errors. I am able to create and save a very simple lisp file. However, when I use the menu function: Mode | Compile and load file I get this: [1] CL-USER(3): ;;; Compiling and loading D:\src\lisp\plus.lisp ... #<THREAD "JLisp interpreter" {FD5428}>: Debugger invoked on condition of type FILE-ERROR The file "D:/src/lisp/srclispplus.lisp" does not exist. It seems that somewhere under the hood the filename gets corrupted. Trying to change the name using double backslashes in the text box above the source file does have no effect. Can I change this behaviour? Thx, Arie

3 8