Re: [Caml-list] Threads and "transaction isolation" in OCaml

[Mark Shinwell <mshinwell@janestreet.com>]

On 17 August 2013 01:06, Yaron Minsky <yminsky@janestreet.com> wrote:
> I'd like to second Markus' request here.  We definitely take advantage
> of this behavior in the compiler, and I hadn't realized that it didn't
> hold in byte-code.  I do think this is a rather valuable hack, and it
> would be good to make the bounds of its applicability more explicit.

I have wondered in the past if we should introduce a syntactic
construct to delimit areas of code that rely on the no-thread-switch
property.  I think it would probably be reasonable to actually
check that the expression inside the construct was guaranteed under
the current runtime not to cause a context switch (such expressions are
likely to be, and should be, straightforward).  At runtime, the
construct would have no semantic effect.  For the scenario described
with bytecode, the construct could just cause a compiler error, at
least at present.

Mark