try-with-resources

[Per Bothner]

On 01/07/2012 01:12 AM, Helmut Eller wrote:
> Just wondering, does Kawa already have somehing like the extened try in
> Java7?

Not yet - though it seems a reasonable thing to add.

A possible syntax:

   (try-with-resources
      ((VAR [:TYPE] INIT) ...)
      BODY)

(The Java "extended" try-with-resources with a catch-clause
or a finally-clause is just a basic try-with-resources
inside of a traditional try statement, so no need to support
that in the Kawa try-with-resources syntax, IMO.)

I haven't looked at the specification closely enough to see if
it can be implemented using a macro only.

I don't know if there is any SRFI or other Scheme that has
something similar, in which case we should consider that as well.

> And would that work on Java6 too?

try-with-resources is defined in terms of java.lang.AutoCloseable,
which is specific to Java7.  It would be plausible for Java6 to
implement a restricted version that uses java.io.Closeable.
Or one could just accept any class with a close method - I don't
know if that would cause problems.

try-with-resources also assumes Throwable#addSuppressed, which
is new in java7, though a java6 "backport" could skip that.
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/