buffered input

[Torarin]

2011/2/5 Andrei Alexandrescu <SeeWebsiteForEmail at erdani.org>:
> I hereby suggest we define "buffered input range of T" any range R that
> satisfies the following conditions:
>
> 1. R is an input range of T[]
>
> 2. R defines a primitive shiftFront(size_t n). The semantics of the
> primitive is that, if r.front.length >= n, then shiftFront(n) discards the
> first n elements in r.front. Subsequently r.front will return a slice of the
> remaining elements.
>
> 3. R defines a primitive appendToFront(size_t n). Semantics: adds at most n
> more elements from the underlying stream and makes them available in
> addition to whatever was in front. For example if r.front.length was 1024,
> after the call r.appendToFront(512) will have r.front have length 1536 of
> which the first 1024 will be the old front and the rest will be newly-read
> elements (assuming that the stream had enough data). If n = 0, this
> instructs the stream to add any number of elements at its own discretion.

This is really cool. I realise now that appendToFront fills the gap in
the design providing only shiftFront/advance. I also thought their
names were well-chosen.

Torarin