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building int[] arrays at runtime
- From: Peter Lane <peter at peterlane dot info>
- To: kawa at sourceware dot org
- Date: Wed, 1 Feb 2017 23:12:33 +0000
- Subject: building int[] arrays at runtime
- Authentication-results: sourceware.org; auth=none
Hi list,
I've been using Kawa as an R7RS implementation for a little while, and
now am using Kawa to work with a Java library. I've hit a little
irritant when calling overloaded methods in Java.
If I build an int[] at runtime, I get a warning about more than one
applicable method. The code seems to run and give the right result, so
the runtime does the right thing. As the warning always appears first,
when the script is loaded, I assume the script is compiled on loading
and so the problem is discovered.
I understand why I'm getting this warning, but wondered if:
a. I should do something other than (apply int[] (list 3)) to create an
int[] at runtime
b. Can I put a compile-time type hint in, to appease/suppress the
initial checks?
I can turn the warnings off with: --warn-invoke-unknown-method=no
but that hides other potential problems, like a mis-spelt method name,
until they trip a runtime exception.
Below is a simple example of what I'm doing:
Java class
----
public class Class1 {
public void show (int[] x) {
System.out.println ("show " + x[0]);
}
public void show (String s) {
System.out.println ("show " + s);
}
}
----
Kawa script
----
(define *x* (Class1:new))
(*x*:show "me")
(*x*:show (int[] 3))
----
and all is fine, I get the expected output:
$ kawa test.scm
show me
show 3
The problem arises when I try building the array at runtime:
----
(define *x* (Class1:new))
(*x*:show "me")
(*x*:show (apply int[] (list 3))); <----- built at runtime
----
$ kawa test.scm
test.scm:3:1: warning - more than one possibly applicable method 'show'
in Class1
candidate: void Class1.show(String)
candidate: void Class1.show(int[])
show me
show 3
thanks,
Peter.
--
Peter Lane
http://peterlane.info/scheme.html