coerce a number to a short

Brad Knotwell bknotwell at
Wed Nov 27 02:28:21 UTC 2019

 I'm pretty sure you're right.  I have a MWE below that shows an unintuitive difference.

(defun void-function ()

  (let* ((result (jstatic "square" "Main" 32)))

    (format t "in void-function, result of calling square(32): ~a~%" result)))

(defun void-function-short ()

  (let* ((result (jstatic "squareshort" "Main" 16)))

    (format t "in void-function, result of calling squareshort(16): ~a~%" result)))



import org.armedbear.lisp.*;

public class Main


    public static int square(int a) {

        return a * a;


    public static int squareshort(short a)


        return a * a;

$ java -cp ~/abcl_excel_gen/abcl-bin-1.6.0/abcl.jar:. org.armedbear.lisp.Main
Armed Bear Common Lisp 1.6.0

Java 11.0.1 Oracle Corporation

Java HotSpot(TM) 64-Bit Server VM

Low-level initialization completed in 0.295 seconds.

Startup completed in 1.663 seconds.

Type ":help" for a list of available commands.

CL-USER(1): (load "lispfunctions.lisp")

in void-function, result of calling square(32): 1024

Error loading /Users/bknotwel/abcl_excel_gen/bug/lispfunctions.lisp at line 11 (offset 358)

#<THREAD "interpreter" {560A10B3}>: Debugger invoked on condition of type ERROR

  no such method


  0: TOP-LEVEL Return to top level.
[1] CL-USER(2):

    On Tuesday, November 26, 2019, 3:53:11 PM PST, Mark Evenson <evenson at> wrote:  

> On Nov 26, 2019, at 18:38, Brad Knotwell <bknotwell at> wrote:
> I've been using ABCL to get access to a Java library and it's worked generally well.  I have run into one problem I haven't been able to workaround.
> I need to make a call to a method that takes a short as an argument.  I'm passing in a value--10--that fits in a short but ABCL can't find the method (presumedly due to a type issue).  I've tried using jcoerce but it's not doing what I expect.  What's the right way to do this?

This is probably a bug in how the Bear’s FFI converts the “10” when it attempts
to locate your specific Java call site, but without a test the contains the
Java code that you are calling into diagnosing exactly what is going in is

When I get the time (or unless someone beats me to it), I will try to make such
a test to figure out what is going on.

We could certainly do with a test suite that combinatorally probes our call
site location logic.

"A screaming comes across the sky.  It has happened before but there is nothing 
to compare to it now."

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