Re: Ann: SWI-Prolog 7.1.0

On 11/26/2013 05:03 AM, Richard A. O'Keefe wrote:
>>     - Unquoted atoms may contain internal dots.  E.g., a.b is an
>> >      atom.
>> >
>> >I find this confusing given V.b is emphatically not an atom.
>> >What's the motivation?

> Could it be the same as Erlang, where lists.iai.uni_bonn.de
> is an atom?

yes.

> (But lists.iai.uni-bonn.de is not; helpful tricks
> that fail at unexpected moments are false friends.)

That is not because of the '.'. It is because _ is allowed in atoms and
some people think this implies - might work too. It doesn't because it
would make useful operator conventions such as pairs key-value
impossible. The situation with . is different. Yes, it can (now) be an
operator, but only in a limited sense because 1.0 is not supposed to
become .(1,0).

>> >    - functor() is valid syntax.  It produces a term that is distinct
>> >      from 'functor'.  The `block' operator '()' to hack this syntax
>> >      has been removed.
>> >
>> >So call(plus(), 2,3,X) is now a thing?
>> >I used to wish for this syntax, but now I can't remember why.

> Something like this used to exist in Poplog and SigmaPROLOG,
> where it was an artefact of representing compound terms as
> (basically) [<atom>|<array>].  As I recall, it was an unmitigated
> nuisance.

We'll see. It breaks nothing as long as you don't use them. It is now at
your disposal. I expect people to find sensible use cases for them, in
particular for designing DSLs. If that proves not to be the case *and*
they prove to be a nuisance, they will probably become an option that
can be enabled using a flag. I prefer to avoid that as I don't like
flags very much. I would be surprised if that happens.

	Cheers --- Jan