OpenEuphoria

Re: Kat's 8bit sequences

• Posted by Dan Moyer <danielmoyer at ?ro?igy.net> Jun 01, 2008
• 714 views

Derek Parnell wrote:
> 
> Dan Moyer wrote:
> 
> > But *if there's no performance hit* for adding 8 bit byte value sequences,
> > then those "others" might be encouraged to use Euphoria, which would
> > generally
> > be recognized as a (mostly) good thing for Euphoria? 
> 
> But that's the point. The current thinking is that Euphoria will actually run
> slower than now if byte sequences were added to the mix of datatypes. And that
> means slower for every Euphoria program not just those using byte sequences.
> 

Ok.  

> The reason goes along the lines that currently, most operations in the backend
> that use datatypes, need to decide what sort of thing it is first; is it an
> integer, an atom, a sequence or an object? There are two bits set aside in the
> 32-bit datatype entity reserved to tell the backend what sort of thing the
> entity
> is. 2-bits means four different possibilities. Now if we add a fifth datatype
> we need to do something clever to identify it. A byte sequence is obviously
> of type of sequence, so we could add to the sequence 'struct' a code that
> differentiates
> between a 32-bit sequence and an 8-bit sequence, but then every backend
> operation
> that deals with sequences will have to do this extra test before it can
> perform
> the operation, because the operation implementation will be different for the
> different sequence types.

Thanks for the explanation Derek. 

> 
> And how many Euphoria programs are there that doesn't use sequences.
> 
> Now, how much of an impact this might be is pure guess work at this time.
> 
> Then there is the new code needed to atually implement efficient 8-bit
> sequence
> operations. And there is a quite a bit of that needed.
> 
> All this is going to take a lot of time to do. So, don't expect 8-bit
> sequences
> to make it in v4.0, but the door is definitely not closed on them. I expect
> that there will be a few experimental editions to test out completing
> implementations
> and to gain insights into how to make it all efficient. As Euphoria is open
> source that means those with expectations for byte sequences can be a part of
> their development.
> 
> I'm very sure that Euphoria will get byte sequences one day, but not right
> away.

Sounds good.

Dan

> 
> -- 
> Derek Parnell
> Melbourne, Australia
> Skype name: derek.j.parnell