Phobos packages a bit confusing

[Andrei Alexandrescu]

bearophile wrote:
> Pelle MÃ¥nsson:
> 
>> foreach (line; open("foobar.txt")) {
>>    writeln(line);
>> }
> 
> With the xio module of my dlibs:
> import d.xio: xfile;
> 
> foreach (line; xfile("foobar.txt"))
>     putr(line);
> 
> xfile is optimized to reduce memory rellocations as much as possible in the most common case of about 90 chars long lines.
> There is an xstdin too.

Why not just reuse the same buffer as the previous line? That approach 
is inherently adaptive. And why is there a need for xstdin vs. xfile? 
Stdin _is_ a file.

Andrei