Re: Ann: SWI-Prolog 7.1.0

 


>> It's not always easy to avoid using defaulty data structures. But the
>> benefits in both code clarity and performance can be quite
>> significant :-) Specially when the defaulty bits are where the
>> application spends most of its time.
> 
> All true.  Just, Prolog systems can also nicely generate a switch-on-tag
> from code such as
> 
> do(X) :- atom(X), ....
> do(X) :- number(X), ...
> do(X) :- string(X), ...
> 
> etc.  Properly implemented, the above should be faster than code like this
> 
> do(atom(X)) :-
> do(number(X)) :-
> do(string(X)) :-
Implementing this kind of optimization would be great, but my experience suggests the discriminator is not usually a basic data type. Thus tagging remains key.