Kawa Generic Functionality

[Nigel Dolby <nigel_dolby at acm dot org>]

As I port Common Lisp code into Kawa there are a number of things that 
would make the process easier, and it would be nice to know if there are 
ways to do these and what they are.

1. The Common Lisp function TYPE-OF accepts absolutely any object and 
returns its type as a symbol; this includes CLOS objects, for which the 
CLOS class is returned. I have written a Kawa function that partially 
implements TYPE-OF by explicitly checking for string, integer, etc in a 
COND, but is it possible also to reliably obtain the type of objects 
defined with DEFINE-SIMPLE-CLASS and of Java objects (without knowing 
that the object in question actually is such a class)?

2. CLOS classes can be given a PRINT-OBJECT method which allows 
customization of the displayed form of an object of that class. I have 
tried attaching a toString method to Kawa classes (made with 
DEFINE-SIMPLE-CLASS) but this doesn't produce the same effect; is there 
a way to do so?

3. I have a function called COPY-CLOS-INSTANCE which clones a given 
instance, optionally using COPY-TREE on any lists it contains. It 
operates by creating a new object and copying each existing slot value 
from the old to the new object. I need this in Kawa. I first tried to 
use the Java 'clone' method, but this generated a protection error at 
compile time. I find that I can obtain the fields of an instance in Kawa 
by invoking getClass followed by getFields, but I have not found any 
definition of the Field objects that are returned. So my code currently 
invokes toString on the Field objects and unmangles the last part of the 
returned string to get the Field name. Is there a more elegant way to do 
this?

4. When a piece of code breaks and control returns to the Kawa 
interactive window, a backtrace is provided that (usually) locates very 
closely the offending source line; is it possible at that point to 
inspect the local variables?

Thanks.


                                                            Nigel Dolby.