On Sat, Dec 6, 2008 at 11:49 AM, Maciej Stachowiak <[EMAIL PROTECTED]> wrote: > > On Dec 5, 2008, at 11:12 PM, Jon Zeppieri wrote: > >> >> I don't get it. What issue is raised by return-to-label that isn't >> already raised by exceptions? They're practically the same thing, >> only return-to-label is *easier* to analyze statically, because >> 'return' can only jump to a label that is lexically (not just >> dynamically) in scope. > > If you want to call a function and make sure control flow does not escape, > then in the face of exceptions alone you can wrap it in try/catch. However, > with multi-level returning lambdas, if you are passed a function then you > have no way to prevent it from returning early, since it could be a lambda > in the lexical scope of your caller.
The strawman contains the following text: "Unwinding the execution context may pass through finally blocks, which execute and may perform their own control effects, effectively canceling the unwinding." So, you have a dynamic-wind-like mechanism, if you need it. Also, what was the performance issue? -Jon _______________________________________________ Es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
