return-from-lambda viewed as dangerous, good alternatives

[Mike Swingler]

On Jan 7, 2010, at 12:45 PM, Stephen Colebourne wrote:

> The whole purpose of John's argument is to leave return free to be
> used in a later JDK for non-local transfer. Lets say that is JDK 8 or
> 9.But given the glacial speed at which many shops upgrade JDK
> versions, this will mean that many developers will face jumping
> straight from JDK 6 to this new JDK 8/9 with non-locals. The same
> problems that Josh described in Devoxx thus re-appear.
> 
> Thus I have some rules I'm following here:
> 1) Developers must be able to trust the 'return' keyword. It must
> never throw a NonLocalTransfer, now or in the future.
> 
> 2) Some other element is allowed to do non-local return and throw a
> NonLocalTransferError, eg 'throw return'.
> 
> 3) If it looks like a method, ie. round-bracketed arguments followed
> by code, then it must be a local return.

+1

In all the mainstream languages that have adopted closures, "return" really means the least surprising thing. I think non-local transfers should have a unique keyword or label syntax or whatever, and should work across traditional methods and closures when their time comes.

Regards,
~Mike