Re: about dynamic/1 and file format

Hi, Jeff,

Thank you very much for your response. As for dynamic, I am talking about
the second one in your response. Because I am trying to establish a
knowledge base in which new facts can be added, I declare :-
dynamic(father/2) at the beginning of my file. When I write all of the
father/2 facts into a new file, I get :- dynamic father/2 at the beginning
of my new file. When I try my program again, :- dynamic father/2 does not
work. So, is there a way to put the parentheses back?

As for file format, I used open/4 and I did specify the file format to be
UTF-8. But, I opened the file with Notepad++, it showed that the file was
the format of UTF-8 without the BOM header. So....

Best,

Hunter

------------------------------------------------------
Wu, Jiun-Shiung, Ph.D.
Professor
Institute of Linguistics
National Chung Cheng University
168, University Road,
Minhsiung, Chiayi County,
Taiwan 621
-------------------------------------------------------


2014/1/6 Jeff Rosenwald <[email protected]>

> Hi Hunter:
>
> On the business of dynamic predicates, it is not entirely clear what you
> are trying to accomplish.
>
> There are two syntaxes for "dynamic" predicates: 1) as a directive (usage
> in the body of a headless predicate), and 2) as an ordinary predicate used
> in the body of a named predicate. The first provides for compile-time
> declaration of dynamic predicates and in that case, the grammar allows you
> to specify one or more name/arity combinations separated by commas. There
> are no parentheses. The second syntax provides for run-time declaration of
> dynamic predicates. It is structured as an ordinary predicate and allows
> exactly one name/arity compound as an argument. I believe that the
> postcondition is the same regardless of the form used.
>
> When writing a text file using Prolog streams, you can specify the
> encoding of the file using the type(text) and encoding/1 options of open/3.
> I believe that you can also use set_set_stream_property/2 as well. When
> writing files (using external editors and such) that you wish to eventually
> consult with SWIPL, you may supply an encoding/1 directive as the first
> line of the file.
>
> Regards,
> Jeff R.
>
>
>
>  -----Original Message-----
> From: Jiun-Shiung Wu <[email protected]>
> To: swi-prolog <[email protected]>
> Sent: Mon, Jan 6, 2014 7:22 am
> Subject: [SWIPL] about dynamic/1 and file format
>
>  Hi, SWI-Prolog users,
>
> I have two questions concerning dynamic/1 and saved file format. I am
> wondering if someone can help me.
>
> I used dynamic to declare that a predicate is dynamic. For example, I put
> :- dynamic(father/2) at the beginning of my file. I used listing(father/2)
> to list all instances of father/2. I found that the parentheses in dynamic
> is gone. That is, when I did listing(father/2), I got: dynamic father/2.
> When I used with_input_to to save all instances of father/2, I got :-
> dynamic father/2 at the beginning of the new file. The parentheses are
> missing. Is there a way not to remove the parentheses in this case?
>
> Secondly, how can I save a file using the UTF-8 with the header BOM? I have
> a knowledge base containing facts written in traditional Chinese (UTF-8).
> When I used with_input_to to save those facts into a new file, the BOM head
> seems to be gone and my Prolog program cannot read it. Though it is easy to
> restore the BOM head using Notepadd++, I am still wondering whether
> SWI-Prolog can save a file using UTF-8 with the BOM head.
>
> Thank you!
>
> Hunter Wu
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