gmane.lisp.allegro

Returning a string from a LISP callable

Myrosia Dzikovska — 2009-10-22T14:20:49

Hello,

I am trying to put together an application in ACL 8.0 where a C++
server periodically calls into LISP (I am integrating with a C++
communications library). It needs to pass a string (char*) argument
into LISP, and return a string (char*) as well.

I can make the callables that pass in a string to LISP, and return
nothing, work. But I cannot return a string sensibly.

So far, I have tried a :returning declaration in
defun-foreign-callable, and setting the convert-to-c-types parameter
in register-foreign-callable to t. In both cases, a null pointer was
returned. I also tried setting a global LISP variable to the return
string value, and accessing it with lisp_value from C. I could not
figure out how the macros in lisp.h work, so the several combinations
I have tried either don't compile, or return a segmentation violation.

If someone could provide me with an example of how this can be done, I
would very much appreciate it.

Myrosia

Weird CLOS MOP behavior

Pascal Costanza — 2009-09-06T20:39:10

Hi,

This is on Allegro 8.1 on Mac OS X.

Assume I have the following definitions:

(use-package :clos)

(defclass my-generic-function (standard-generic-function)
   ()
   (:metaclass funcallable-standard-class))

(defmethod compute-discriminating-function ((mf my-generic-function))
   (let ((disc (call-next-method)))
     (lambda (&rest args)
       (print args)
       (apply disc args))))

(defgeneric foo (x y z)
   (:method (x y z) (+ x y z))
   (:generic-function-class my-generic-function))


If I load and test these definitions, I get the following output:

CL-USER(1): (load "clos-test")
; Fast loading /Users/costanza/Muell/clos.fasl

(#<Closure (:INTERNAL
             (METHOD COMPUTE-DISCRIMINATING-FUNCTION
              (MY-GENERIC-FUNCTION))
             0)
    < at > #x1000aa8bb2>)
T
CL-USER(2): (foo 4 5 6)

(4 5 6)
(#<Function (METHOD FOO (T T T))>)
15
CL-USER(3): (foo 4 5 6)

(4 5 6)
15


Does anybody have an idea where the internal closer and functions come  
from that seem to be passed to the discriminating function? Is there a  
way to suppress that? This makes it hard to write portable extensions  
of generic functions...


Thanks a lot for any hints...


Pascal

auto load after start

phil — 2009-08-18T14:26:44

Hello,

I have a simple question. I just want to load a lisp file
automatically after start up. Important is, that the package
COMMON-GRAPHICS-USER has already been loaded. By using the attribute
-L the file will be loaded with the COMMON-LISP-USER package, which
won't work with my lisp file. What can I do?

Thanks for help,
Phil

European Common Lisp Meeting

Arthur Lemmens — 2009-08-07T13:14:51

Hi,
 
We just want to remind you that the registration deadline for this year's
ECLM (European Common Lisp Meeting) is August 15.  You can still register
at
 
  http://weitz.de/eclm2009
 
We hope to see you in Hamburg,
 
Edi Weitz & Arthur Lemmens