Proposal for SentinelInputRange

[timotheecour]

On Thursday, 28 February 2013 at 01:56:33 UTC, Walter Bright 
wrote:
> On 2/27/2013 5:53 PM, Zach the Mystic wrote:
>> What if more than one
>> value can end the range, EOF, '\0'?
>
> I have never seen a need for that.

how about a predicate isSentinel instead of a fixed sentinel 
value?
That'd allow more flexibility such as more than one sentinel 
value.