> On 4 Apr 2018, at 17:32, K K Subbu <kksubbu...@gmail.com> wrote:
>
> On Wednesday 04 April 2018 04:06 PM, Nicolas Cellier wrote:
>>> IIRC, someone said it is implemented as 'remaining size being zero'
>>> and some virtual unix files like /dev/random are zero sized.
>> Currently, for files other than sdio (stdout, stderr, stdin) it is
>> effectively defined as:
>> atEnd := stream position >= stream size
> I see a confusion between Stream and its underlying collection. Stream is an
> iterator and just does next, nextPut, peek, reset etc. But methods like size
> or atEnd depend on its collection and there is no guarantee that this
> collection has a known and finite size.
>
> Essentially, a collection's size may be known and finite, unknown but finite
> size or infinite. This has nothing do with file descriptor being
> std{in,out,err}. If std* is a regular file or special file like /dev/mem,
> /dev/null, it's size is known at open time. With console streams or sysfs
> files, size is unknown until EOT (^D) or NUL is received. Lastly, special
> files like /dev/zero, /dev/random or /proc/cpuinfo don't have a finite size
> but report it as zero (!).
>
> [ stream atEnd ] whileFalse: [ stream next. .. ]
>
> will only terminate if its collection size is finite. It won't terminate for
> infinite collections.
>
> Regards .. Subbu
Good summary, I agree.
Still, what are the semantics of #next - does the caller always have to check
for nil ? Do we think this is ugly (as the return value is outside the domain)
? Do we then still need #atEnd ?
Sven
