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Re: Get DCG error (on any DCG clause)

From: Fergus Henderson
Subject: Re: Get DCG error (on any DCG clause)
Date: Mon, 19 Nov 2001 19:06:00 +1100

On 19-Nov-2001, address@hidden <address@hidden> wrote:
> Ive just installed Gprolog under linux and I'm trying to use DCGs. but
> ...
> [user].
>       Program --> A,[a].
> gives:
>       DCG error raised: instantiation_error.

The head of a DCG clause can't be a variable,
i.e. it can't start with a capital letter.

        program --> a, [a].

Of course then you'll need a definition for "a",

        a --> ...

Fergus Henderson <address@hidden>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <>  |     -- the last words of T. S. Garp.

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