Re: Ann: SWI-Prolog 6.5.3

On Wed, Nov 20, 2013 at 8:05 PM, Richard A. O'Keefe <[email protected]>wrote:

>
> On 20/11/2013, at 10:43 PM, Jan Wielemaker wrote:
> [about the new behaviour of memberchk/2]
> > Even if
> > possible, I still do not like that, as it will imply that strings may
> > silently be transformed into code lists.
>
> Now I am puzzled and confused.  The point of the NU Prolog approach
> was that strings *were* lists, it's just that some strings were stored
> more compactly than others.  It meant, for example, that you could have
> large amounts of text data in static code.
>
> ...
>
> In the same way, in the NU Prolog approach, a byte-per-element string
> *IS* a code list, just stored differently.
>

I think this is an important point worth extra attention.  In one sense,
[H|T] is just a comfortable interface for sequences of data.  A linked list
is the traditional sequence, but string-stored-as-byte-array is a sequence
too.  A sequence might be the key-value pairs in a map or the bytes in a
stream, etc.  Clojure sequences take the idea to its conclusion by
abstracting the cons interface so that many data structures can implement
it.

I'd love to see this idea in more Prologs.

-- 
Michael
-------------- next part --------------
HTML attachment scrubbed and removed