nl/1 in SICStus prolog

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2 total messages Started by Roland Paterson-Jones Thu, 29 Oct 1992 15:49

#19

Author: Roland Paterson-Jones
Date: Thu, 29 Oct 1992 15:49

17 lines
1055 bytes

While running a prolog program written in SICStus, our SBProlog3.1 whinged
about the predicate nl/1:

> process_back_arcs:-
>     retract(arc(X,Y,back)),
>     display('processing a new back'), nl(user_output),
>     ( node(Y,I_Y,_) -> true ),	^^^^^^^^^^^^^^^
>     find_cycles([Y],X,I_Y,[Y]),
>     process_back_arcs.

What is this intended to do, and what is the significance of the atom
'user_output'?

--
Roland P-Jones			aka roland@uctcs.cs.uct.ac.za
University of Cape Town		 or roland@sun-2.cs.uct.ac.za
South Africa

Re: nl/1 in SICStus prolog

#26

Author: Cerebus
Date: Fri, 30 Oct 1992 16:08

27 lines
1670 bytes

roland@sun-2.cs.uct.ac.za (Roland Paterson-Jones) writes:

>While running a prolog program written in SICStus, our SBProlog3.1 whinged
>about the predicate nl/1:

>> process_back_arcs:-
>>     retract(arc(X,Y,back)),
>>     display('processing a new back'), nl(user_output),
>>     ( node(Y,I_Y,_) -> true ),	^^^^^^^^^^^^^^^
>>     find_cycles([Y],X,I_Y,[Y]),
>>     process_back_arcs.

>What is this intended to do, and what is the significance of the atom
>'user_output'?

Unless I'm very much mistaken, this is intended to send an end-of-line
character to whatever user_output has been defined as (the console, a
file, etc.), and move to the next line.

-- Matt
+------------------------------+------------------------------------------+
|  Matt "Matt" Blum            | Let's make George Bush the 33rd          |
|                              |     ex-President of the United States!   |
| mblum@cs.brandeis.edu        |                                          |
|                              | I am not politically incorrect.          |
|  (617)736-5894               | I am politically challenged.             |
+------------------------------+------------------------------------------+

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