Subject: Directional programs in SWIPL ?

From: "F.G. van DORP" <[email-masked]>
Date: Tue, 17 Oct 2000 17:31:41 +0200

Is it possible to write directional "functions" in SWI-Prolog, where only
the "return" variables (Rn's below, the Vn's must be ground) can be
written to, e.g.:

  p1(V1, V2, ..., R1)  :-  p2(..., R2), p3(..., R2, ..., R3), ..., pn(..., R1).

and ,if so, would there be a performance bonus (I just can't seem to
find any mode declaration options in the manual or am I missing the
obvious here) ?

Thanks,
Bob.
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