🚀 go-pugleaf

|>    P ;_Q :- P.
|>    _P; Q :- Q.
|> 
|> SICStus Prolog does nothing special, and considers it as an ordinary
|> predicate as you describe.

You certainly do not do so!
Consider the above example:

go1(X) :- foo(X), ( ! ; true).
go2(X) :- foo(X),  or(!, true).

foo(1).
foo(2).

or(P,_) :- P.
or(_,Q) :- Q.

Executing this in SICSTUS gives:

| ?- go1(X).

X = 1 ? ;

no
| ?- go2(X).

X = 1 ? ;

X = 1 ? ;

X = 2 ? ;

X = 2 ? ;

no
| ?- ^D
{ End of SICStus execution, user time 0.060 }


Is it a kind of remake for "go2 considered harmful" ? :-)


More seriously, how do you treat the so-called "transparency" of the cut ?