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devel / comp.lang.prolog / Re: About the Operator '|' and the DCG Draft

Re: About the Operator '|' and the DCG Draft

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Subject: Re: About the Operator '|' and the DCG Draft
From: burse...@gmail.com (Mostowski Collapse)
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by: Mostowski Collapse - Sun, 10 Apr 2022 21:22 UTC

But now things get funky, this example does also not work.
Is there a systemic error in the SWI-Prolog table or its handling?
In that something is systematically flipped by some error that

happend once? Here the result, doesn’t agree with Table 6:

/* SWI-Prolog */
?- op(9,xfy,xfy), op(9,yfx,yfx).
true.

?- X = (1 xfy 2 yfx 3), write_canonical(X), nl.
yfx(xfy(1,2),3)
X = 1 xfy 2 yfx 3.

On the other hand, this agrees:

/* GNU Prolog */
?- op(9,xfy,xfy), op(9,yfx,yfx).
yes
?- X = (1 xfy 2 yfx 3), write_canonical(X), nl.
xfy(1,yfx(2,3))
X = 1 xfy 2 yfx 3

Also changing the associativity rule tables of the parser, what will
happen to the unparser in SWI-Prolog? Does it use the same
associativity rule tables, from a single point?

Subject	Author
About the Operator '\|' and the DCG Draft	Mostowski Collapse