getMethod() works and works not

[Alexander Burger]

What is the getMethod translation? Does the class in question have an
"add" method member, either by declaration or inheritance, with the

Oops, you are right. I forgot to fix that line when preparing a reduced
example. 'JTextArea' should have been the variable 'area'. Anyway, it
works now

Thanks.

 

[Alexander Burger]

3. Reject the ones with the wrong number of arguments. (Be careful here if
you're going to support variable-argument methods)

I won't. This would introduce too much runtime overhead. Instead I'll go with
passing arrays. The following works:

(java "java.lang.String" "format" "%4$2s %3$2s %2$2s %1$2s" '("a" "b" "c" "d"))

 

[Alessio Stalla]

To begin with, why is the OP using reflection at all?  It's of no value in
the code actually posted, which could simply call method the normal way..

Sure, but this is just a prepared, reproducible example.

The actual code is the Java version of PicoLisp. The plain runtime
system ist at "http://software-lab.de/ersatz.tgz", the full system
including sources at "http://software-lab.de/picoLisp.tgz".

There is a generic 'java' function which allows to call arbitrary
constructors and methods, on arbitrary objects. And, this indeed works
most of the cases, but sometimes (like here for 'JPanel' and 'add') not.

The lisp-level function 'java' accepts four syntax patterns:

   (java 'obj ['cnt]) -> any
      Converts a Java object back to Lisp data

   (java 'obj 'msg 'any ..) -> obj
      Invokes a method 'msg' on an object 'obj' with arguments 'any'

   (java 'cls 'msg 'any ..) -> obj
      Invokes a static method 'msg' in class 'cls' with arguments 'any'

   (java 'cls 'T 'any ..) -> obj
      Returns a new object of class 'cls' by calling the constructor of
      that class with arguments 'any'.

For example, this works (analog to the posted plain Java example):

   (setq
      frame (java "javax.swing.JFrame" T "Title")
      panel (java frame "getContentPane")
      area (java "javax.swing.JTextArea" T 10 40) )

   (java frame "setSize" 300 200)
   (java frame "setLocation" 100 100)

   # ??? (java panel "add" JTextArea)

   (java frame "setVisible" T)

Just the line with "???" does not, and this is the case which also has
"???" in the original post.

You can have a look at how ABCL does it. Your java operator is called
jcall in ABCL, and it does perform some dynamic dispatch in the vein
of what javac does for method resolution; though it probably isn't
100% compatible with what the JLS specifies, it's "good enough" for
the cases we encountered so far. Some pointers:

(incomplete) documentation of ABCL's Java FFI:
http://trac.common-lisp.net/armedbear/wiki/JavaFfi

Implementation of jcall and other primitives:
http://trac.common-lisp.net/armedbear/browser/trunk/abcl/src/org/armedbear/lisp/Java.java

ABCL home page: http://common-lisp.net/project/armedbear

Cheers,
Alessio

 

[Alexander Burger]

Thanks Alessio. However, with the help of the previous posters to this
thread I've already got it running. I used it to solve a RosettaCode
task (though with a rather large amount of inline Java coding):

http://rosettacode.org/wiki/Image_Noise#PicoLisp

Cheers,
- Alex

 

[markspace]

Thanks Alessio. However, with the help of the previous posters to this
thread I've already got it running. I used it to solve a RosettaCode
task (though with a rather large amount of inline Java coding):

http://rosettacode.org/wiki/Image_Noise#PicoLisp

What was your frames per second?

 

[Alexander Burger]

What was your frames per second?

I measured slightly over 100 frames per second on an old
IBM ThinkPad (Pentium M)