[r6rs-discuss] Thoughts on Scheme's Future

[Grant Rettke]

On Fri, Sep 4, 2009 at 3:30 PM, Joe Marshall<jmarshall at alum.mit.edu> wrote:
> On Fri, Sep 4, 2009 at 1:21 PM, Anton van
> Straaten<anton at appsolutions.com> wrote:
>> Joe Marshall wrote:
>>> Similarly with threads.  These are a disaster.  It is very hard to program with
>>> concurrency.  It is harder still if your concurrancy mechanism is something
>>> as primitive as a thread.  In nearly every implementation of Common Lisp
>>> I've worked on, they've made major errors in concurrency control.  And these
>>> are the *vendors*.  The users have no hope of getting it right.
>>>
>>> I don't know what the correct solution to concurrency is, but I'm sure we
>>> can do better than a thread library.
>>
>> I don't know what the correct solution to control flow is, but I'm sure
>> we can do better than first-class continuations.
>
> Agreed.  Although this could be interpreted in two different ways, both of which
> I agree with.
>
>    1.  Easier to understand user constructs such as structured
> exceptions, non-local
>         exits, co-operative co-routines, etc. should be what users turn to
>         rather than ad-hoc grabbing of continuations.
>
>    2.  First-class continuations should NOT be used as a model or
>         implementation of threads.  (You can crudely mimic time-division
>         multiplexing, but not true asynchronous parallel computation.)

Is this part of the language specification or the "standard library"?