jbee/jadamant — Issue #25: Refine Sequence-interface family 
Author: jbee
Created: 2012-02-21 11:43:32+00:00
State: open

##### `ModifyableSequence`
Usage has shown that there are different constraints upon modifications. It might be hard or impossible to support some and easy to support others. One set identified are those modifications that just narrow a sequence by removing elements at front or tail. This can easily be supported by just have a _pointer_ to the first (and/or last) element and use that as an offset.

##### `Stream`s
We should also find a common base interface for sequences having a determinable number of elements (a known `length()`) and those that don't like a stream of elements. Both could support `isEmpty()`.

It would also be nice to have a `Stream` that can be treated as if it is immutable in sense of the picture (of the stream) it provides to it's callers. Maybe there can be some kind of buffer so that you can _view_ at that stream at a previous point in time but that _view_ might be invalidated when the buffer is flow over so it _reuses_ that buffer cells again for a later _view_ on the same physical stream.