> On 2 Nov 2017, at 10:10 , Guillermo Polito <guillermopolito@gmail.com> wrote:
>
> My first hunch is that you don't want to change PositionableStream. Because it works on collections and files (because of inheritance). But not on other kind of streams that are not part of the hierarchy, such as sockets. And we are cleaning that part.
>
> Instead, some time ago Sven produced a really nice hierarchy of stream decorators. Check the package:
>
> Zinc-Character-Encoding-Core
>
> There you have
>
> ZnBufferedReadStream
>
> That implements buffering in an orthogonal way. Maybe it makes more sense to put such method there?
>

I wanted this to be something light-weight.�� I really don���t want to have to wrap my stream in a decorator before peeking ahead.

Because I���m doing this in SmaCC, I implemented #explore: (that���s the name I chose) in SmaCCLineNumberStream.�� ��But I think that the general solution is to put this method in a Trait, so that it can be combined into any stream, whether or not that stream inherits from PositionableStream.�� There are probably other methods that could go in such a trait too.

Actually, the idea of resetting a stream to a prior position is much less general, and easier to implement, then general positionability.�� Over the weekend I posted an issue that discusses positioning a MultiButeFileStream ��� that���s a good example.

Here is my implementation ��� really simple.

```
explore: aBlock
�� �� �� �� "evaluate aBlock with this stream as argument.�� When done, reset my position to the current position."

�� �� �� �� | savedPosition |
�� �� �� �� savedPosition := self position.
�� �� �� �� [ ^ aBlock value: self ] ensure: [ self position: savedPosition ]
```

�� �� �� �� Andrew