Retrieving the traversed range

[Peter Alexander]

On 29/08/10 2:01 AM, Andrei Alexandrescu wrote:
> On 08/28/2010 07:06 PM, Manfred_Nowak wrote:
>> In your OP you wrote:
>>> but Until is (correctly) not bidirectional
>>
>> I recognize at least a misunderstanding in this sentence, because every
>> bidirectionalRange _is_ an inputRange. Therefore `Until!' _should_
>> work on
>> every bidirectionalRange.
>
> It does, it just yields (only) a forward range. The allBefore() thing is
> only in the discussion stage.

Is that implying that Until will become bidirectional when/if allBefore 
is added?

How?

Until is supposed to be lazy, so how could you retrieve 
until!pred(r).back without walking the range until pred is satisfied?

Or have I misinterpreted you, and Until is going to remain a forward range?