From john.ogorman@zombie.co.nz Tue Nov  5 11:42:19 2002
From: John O'Gorman <john.ogorman@zombie.co.nz>
To: ciao-users@cliplab.org
Subject: Re: curly braces
Date: Tue, 05 Nov 2002 11:42:12 +0100
Message-ID: <15815.41092.190197.846556@salmon.ls.fi.upm.es>
In-Reply-To: <200211041605.gA4G5I7r016352@webmail2.magma.ca>
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Gregory Bourassa wrote:
>=20
> John,
>=20
> They are used in Definite Clause Grammar (DCG) clauses to enclose a
> Prolog expression (term) which will not be translated by the grammar
> translation.  As you may know, the DCG clauses are translated into
> plain Prolog clauses which take care of handling the lists of input
> tokens over which the grammar will be applied.  This saves you writing
> the list-handling part of things, which can be boring and error-prone.
> The terms enclosed in curly brackets are included in these translated
> clauses, but without change.  You generally use them to state logical
> relations about things in the grammar.

Aha!
Thank you Gregory. What a brilliant explanation!

John O'Gorman
>=20
> Regards.
>=20
> Gregory Bourassa
>=20
> On Nov 04, "John O'Gorman" <john.ogorman(a)zombie.co.nz> wrote:
> >
> >
> > Hi people
> >
> > Can anyone tell me the meaning of {} in prolog.
> > Claudi Marcus has examples of terms within curly
> > braces in her book. Also Prolog: The Standard
> > has then in its syntax diagrams.
> >
> > But I cannot find any explanation of their meaning.
> >
> > John O'Gorman
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D
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=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D
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