Re: Inconsistency in rescuability of "return"

On Jan 2, 2008, at 7:15 PM, Jano Svitok wrote:

> On Jan 3, 2008 12:53 AM, Gary Wright <[e-mail]> wrote:
>>
>> On Jan 2, 2008, at 6:31 PM, Charles Oliver Nutter wrote:
>>> But when eval'ing a break outside a while, it does propagate an
>>> error. So the code under eval is changing its behavior depending on
>>> what structures surround it. That seems wrong to me, and it means
>>> that any implementations wanting to emulate it will have to
>>> maintain state across calls, so eval knows it's being called within
>>> a loop.
>>
>> I don't see how this is any different than the other examples.  When
>> "eval 'break'" is inside the while loop, 'break' doesn't cause an
>> error, it simply breaks out of the loop.  If you put "eval 'break'"
>> at the top level you've got your local jump error again, right?
>
> The issue is that eval result depends on one more variable - whether
> the call is inside a loop or not.
> So it's a function of it's parameters, data, AND previous calls (or
> how you would call it).

Yes, but the behavior of 'break' itself is dependent on the context.   
So it is the semantics of 'break' that seems to be in question in  
this example, not the semantics of 'eval' and the semantics of break  
in this example are 'normal' as far as I can tell:

A) break (via eval or not) outside of a loop context causes an exception
B) break (via eval or not) inside a loop context causes the loop to  
be terminated

If this is problematic, what behavior would you expect for A and B?

Gary Wright