Re: How to implement immutable ring buffer?

2015-05-27 Thread drug via Digitalmars-d-learn

On 27.05.2015 11:10, Daniel Kozák via Digitalmars-d-learn wrote:


On Wed, 27 May 2015 09:20:52 +
drug via Digitalmars-d-learn  wrote:


Could somebody share his thoughts on the subject?
Would it be efficient? Is it possible to avoid memory copying to
provide immutability? To avoid cache missing ring buffer should be
like array, not list, so it's possible that the whole buffer should
be moved. Is it neccessary to be real immutable, may be some form of
fake immutabitiy is enough?
I'd like to try immutability in my app, and ring buffer is what I
don't know how to use in the realm of immutability.

Thanks


Maybe http://dlang.org/phobos/std_typecons.html#.Rebindable could help
you.

I guess it won't be efficient, because it would be ring buffer of (in 
some form) pointers. It's suitable if elements of the buffer are 
processed independently each other. In other case cache misses are 
provided, I think.


Re: How to implement immutable ring buffer?

2015-05-27 Thread drug via Digitalmars-d-learn

On 27.05.2015 11:04, thedeemon wrote:

This whole idea sounds self-contradictory.
Ring buffer is a mutable-array-based implementation of something, for
example of a queue. You can ask about immutable implementations of a
queue, but that would be another question, not involving a ring buffer.

What do you want to do with this buffer, what do you need it for?
In general I need to have the last n instances of some objects queue. 
Now it implemented using ring buffer. Probably, you're right about 
immutable queue, it is more suitable definition here.


Re: How to implement immutable ring buffer?

2015-05-27 Thread Daniel Kozák via Digitalmars-d-learn

On Wed, 27 May 2015 09:20:52 +
drug via Digitalmars-d-learn  wrote:

> Could somebody share his thoughts on the subject?
> Would it be efficient? Is it possible to avoid memory copying to
> provide immutability? To avoid cache missing ring buffer should be
> like array, not list, so it's possible that the whole buffer should
> be moved. Is it neccessary to be real immutable, may be some form of
> fake immutabitiy is enough?
> I'd like to try immutability in my app, and ring buffer is what I
> don't know how to use in the realm of immutability.
> 
> Thanks

Maybe http://dlang.org/phobos/std_typecons.html#.Rebindable could help
you.


Re: How to implement immutable ring buffer?

2015-05-27 Thread thedeemon via Digitalmars-d-learn

This whole idea sounds self-contradictory.
Ring buffer is a mutable-array-based implementation of something, 
for example of a queue. You can ask about immutable 
implementations of a queue, but that would be another question, 
not involving a ring buffer.


What do you want to do with this buffer, what do you need it for?