Re: R7RS Libraries and Java interaction

[Per Bothner <per@bothner.com>]

On 03/22/2017 01:55 PM, Peter Lane wrote:

> Is it possible to make an R7RS library recognise Java interaction when compiled?
>
> e.g. if I try compiling the following:
>
> (define-library (java)
>                 (export get-num)
>                 (import (scheme base))
>
>                 (begin
>                   (define (get-num) ((String "hello"):length))
>                 ))
>
> $ kawa --r7rs -C java.sld(compiling java.sld to java)
> java.sld:7:54: warning - no declaration seen for :length

It seems to work if you leave off the --r7rs flag.

The --r7rs disables features that conflict with R7RS, such as the special
meaning of colon, since in R7RS colon is just a regular symbol character.
You don't need it for this example.

> $ kawa --r7rs try-java.sps java.sld:7:54: unbound location: :length
>     at gnu.mapping.SharedLocation.get(SharedLocation.java:22)
>     at gnu.mapping.DynamicLocation.get(DynamicLocation.java:28)
>     at java.getNum(java.sld:7)
>
> If I rewrite get-num to use invoke, I still get compilation warnings, but it works at runtime.

That can be fixed by adding:

    (import (only (kawa base) invoke))
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/