Range of chars (narrow string ranges)

[Martin Nowak via Digitalmars-d]

On 04/24/2015 10:44 PM, Walter Bright wrote:
> 4. Autodecoding is inefficient, especially considering that few
> algorithms actually need decoding. Re-encoding the result back to UTF8
> is another inefficiency.
> 
> I'm afraid we are stuck with autodecoding, as taking it out may be far
> too disruptive.
> 
> But all is not lost. The Phobos algorithms can all be fixed to not care
> about autodecoding. The changes I've made to std.string all reflect that.

It probably won't be too disruptive to optimize algorithms such as
filter to return a range of chars, but only if we support such ranges as
narrow strings everywhere.