iota with custom boundary conditions

[Joseph Rushton Wakeling]

On 11/13/2012 04:11 PM, Joseph Rushton Wakeling wrote:
> It's maybe not the most important use-case, but if the change can be introduced
> in a non-breaking way, why not?

Actually, this was probably the main reason I brought it up: _is_ it possible to 
do this as a non-breaking change?  In principle I'd think so, but then again if 
someone has actually written something like,

     auto r = iota!(size_t, size_t, size_t)(0, 200, 2);

... then introducing a default form of

     iota(string boundaries = "[)", B, E, S)(B begin, E end, S step)

would break, no?  Nevertheless, is it worth entering as a feature request?