Exception transparency

[Neal Gafter]

On Mon, Jun 7, 2010 at 9:53 PM, Reinier Zwitserloot <reinier at zwitserloot.com
> wrote:

> Making the exceptions transparent by encoding them in the type system is
> going to be very unwieldy, even if a "throws T" variadic type parameter
> concept is introduced. I've got a much better idea: Escape detection on
> closures. Any closures that are guaranteed to run such that the runtime
> stack matches the lexical stack can get exception transparency completely
> free, no new syntax and no new concepts required; it would "just work".
>

Reinier: your scheme, even assuming it could be checked at compile-time,
does not work for functions that are to be stored in variables or in a data
structure (for example, a collection of callback functions).  It is not
composable.