[phobos] Improvement of stream

[Andrei Alexandrescu]

I understand this concern. Nowadays I have found use for a different 
concept - range with history. With such a range you can return in "time" 
to positions that you've visited before. There's also the concept of 
"lookahead", i.e. a range that you can move to later points in time.

A seekable file would be a range with both history and lookahead. 
Anyway, such adaptors are generally useful - I was thinking of defining 
Lookbehind(Range) and Lookahead(Range) in std.range. They'd use RAM for 
caching.


Andrei

On 07/05/2010 11:57 AM, Michel Fortin wrote:
> Le 2010-07-05 à 12:23, Andrei Alexandrescu a écrit :
>
>> On 07/05/2010 11:14 AM, Michel Fortin wrote:
>>> But I have to admit the ability of a range to seek outside of the range's range (like rewinding) seems a little odd. It does fit better with a 'stream' concept.
>>
>> Ranges are streams!
>
> I'm not contesting that (at this time). What I meant is that allowing a range to seek beyond its bounds looks counter nature to me. If it was called a stream it wouldn't be so bad. It's mostly a naming thing.
>
> For instance, let's say I have a file with this content:
>
> 	[0,1,2,3,4,5,6,7,8,9];
>
> I call popFront 5 times, so the content of the range conceptually becomes this:
>
> 	[5,6,7,8,9];
>
> Then I call a function, say seek(2), to return to the third element. Does this add back elements in my range?
>
> 	[2,3,4,5,6,7,8,9]
>
> Adding back elements to a range seems quite un-range-like to me. Seeking to a position relative to the first element in the "container" (the file) would be even more so.
>
> Now call it a stream and it looks more natural to do these operations. But perhaps it's only me.
>
>