Re: Interaktion between Scheme and Java

[Per Bothner <per at bothner dot com>]

Marco Bakera wrote:
> On 2/22/06, Per Bothner <per@bothner.com> wrote:
 > But there is some other problem I didnt master yet. A while ago[1]
> Shoeb wrote the following to the list.
>
> > I have a list of Java objects in a Java list (e.g. java.util.ArrayList).
> >
> > I have a scheme function that takes a Scheme list as a parameter.
> >
> > How do I pass my Java list to the scheme function?
> >
> > (In my scheme function I want to treat the list as a Scheme list so that I
> > can invoke 'car' and 'cdr' on it.)
> >
> > I tried creating a new Pair() object in my Java code, adding my Java objects
> > to it (using the 'add' method since Pair implements the List interface), and
> > passing it as an argument to the scheme function. I get the following
> > exception:

Pair is the wrong place to look, since converting a zero-size java.util.List
to a Scheme list should return an empty list - which contains no Pairs.

The right place to look is Pair's super-class gnu.lists.LList, which
has the makeList convenience function:
http://www.gnu.org/software/kawa/api/gnu/lists/LList.html#makeList(java.util.List)

Unfortunately, no documentation, but it should be fairly obvious.
--
	--Per Bothner
per@bothner.com   http://per.bothner.com/