Re: some questions using callbacks to java

[Per Bothner <per at bothner dot com>]

"Paul R. Potts" <potts@umich.edu> writes:

>             (begin
>                 (invoke debug-callbacks 'print "script point 1")
>                 (invoke parameter-callbacks 'test_bind "patient")
>                 (invoke debug-callbacks 'print patient)
>             )
> 
> when i evaluate the kawa body i get
> 
> <string>:1:332: warning - no method `print' in java.lang.Object
> <string>:1:381: warning - no method `test_bind' in java.lang.Object
> <string>:1:427: warning - no method `print' in java.lang.Object
> 
> is there a way to avoid these warnings going to stdout?

I could disable these warning with some switch, I suppose.  However, the
warning means that the compiler is forced to generate code to look up
the method at run-time.  I haven't timed it, but I would not be surprised
is doing that is *100 times* slower than if the compiler can find the
method.

The prferred ay to avoid the warnings is to use declarations, assuming
debug-callbacks etc are lexicall bound.  If not you can put in an
explicit cast:

(invoke (as <java.util.Date> my-date) 'setDate cur-date)

I don't know how well this would work with inner classes.

> the first callback works, then the test_bind fires. it appears to execute
> ok, but then when executing the next callback i get
> 
> Unbound Symbol exception: Unbound symbol patient

"patient" does not evaluate to a Java String - it's a Scheme string.
Use 'patient instead.
-- 
	--Per Bothner
per@bothner.com   http://www.bothner.com/~per/