[PPL-devel] Bignums

[Roberto Bagnara]

Hi there,

I believe the following behavior of the CVS version of YAP
witnesses a bug (or, quite possible, a misunderstanding on my part):

$ yap
[ Restoring file /usr/local/lib/Yap/startup ]
[ YAP version Yap-4.3.23 ]
    ?- current_prolog_flag(bounded,X).

X = false ?
    ?- X is 333333333333333, integer(X).


no
    ?- X is 33333333, integer(X).

X = 33333333 ?
    ?- X is 333333333333333, float(X).

no
    ?- X is 333333333333333, number_chars(X,L).

X = 333333333333333,
L = [51,51,51,51,51,51,51,51,51,51,51,51,51,51,51] ?

In words, the Prolog engine first declares it is employing
unbounded integers, then it silently converts an integer
numeral to... to what?
Is this a bug?  Am I missing something?
All the best

     Roberto

-- 
Prof. Roberto Bagnara
Computer Science Group
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara at cs.unipr.it