Include Paulo Moura's Logtalk OO LP system

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Logtalk/examples/parametric/NOTES

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+=================================================================
+Logtalk - Object oriented extension to Prolog
+Release 2.8.4
+
+Copyright (c) 1998-2001 Paulo Moura.  All Rights Reserved.
+=================================================================
+
+To load most objects in this example consult the parametric.loader 
+utility file (note that the *.loader files are Prolog files).
+
+This folder contains two examples of parametric objects dealing
+with time and date values.

Logtalk/examples/parametric/SCRIPT

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+=================================================================
+Logtalk - Object oriented extension to Prolog
+Release 2.8.4
+
+Copyright (c) 1998-2001 Paulo Moura.  All Rights Reserved.
+=================================================================
+
+
+% some queries using the time and date parametric objects:
+
+| ?- date(Year, Month, Day)::today.
+
+Year = 2000
+Month = 8
+Day = 15 
+
+Yes
+
+
+| ?- date(Year, _, _)::(today, leap_year). 
+
+Year = 2000
+
+yes
+
+
+| ?- time(Hours, Mins, Secs)::now.
+
+Hours = 13
+Mins = 52
+Secs = 42 
+
+Yes

Logtalk/examples/parametric/date3.lgt

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+
+:- object(date(_Year, _Month, _Day)).
+
+
+	:- info([
+		version is 1.0,
+		authors is 'Paulo Moura',
+		date is 1998/3/23,
+		comment is 'Dates as parametric objects.',
+		parnames is ['Year', 'Month', 'Day']]).
+
+
+	:- public(year/1).
+	:- mode(year(?integer), one).
+
+	:- public(month/1).
+	:- mode(month(?integer), one).
+
+	:- public(day/1).
+	:- mode(day(?integer), one).
+
+	:- public(today/0).
+	:- mode(today, one).
+
+	:- public(leap_year/0).
+	:- mode(leap_year, zero_or_one).
+
+
+	year(Year) :-
+		parameter(1, Year).
+
+
+	month(Month) :-
+		parameter(2, Month).
+
+
+	day(Day) :-
+		parameter(3, Day).
+
+
+	today :-
+		{lgt_current_date(Year, Month, Day)},
+		parameter(1, Year),
+		parameter(2, Month),
+		parameter(3, Day).
+
+
+	leap_year :-
+		parameter(1, Year),
+		(0 is mod(Year, 4),
+		 0 is mod(Year, 100)
+		 ;
+		 0 is mod(Year, 400)),
+		!.
+
+
+:- end_object.

Logtalk/examples/parametric/parametric.loader

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+
+:- initialization(
+	logtalk_load([
+		date3,
+		time3])).

Logtalk/examples/parametric/time3.lgt

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+
+:- object(time(_Hours, _Mins, _Secs)).
+
+
+	:- info([
+		version is 1.0,
+		authors is 'Paulo Moura',
+		date is 1998/3/23,
+		comment is 'Time as parametric objects.',
+		parnames is ['Hours', 'Mins', 'Secs']]).
+
+
+	:- public(hours/1).
+	:- mode(hours(?integer), one).
+
+	:- public(mins/1).
+	:- mode(mins(?integer), one).
+
+	:- public(secs/1).
+	:- mode(secs(?integer), one).
+
+	:- public(now/0).
+	:- mode(now, one).
+
+
+	hours(Hours) :-
+		parameter(1, Hours).
+
+
+	mins(Mins) :-
+		parameter(2, Mins).
+
+
+	secs(Secs) :-
+		parameter(3, Secs).
+
+
+	now :-
+		{lgt_current_time(Hours, Mins, Secs)},
+		parameter(1, Hours),
+		parameter(2, Mins),
+		parameter(3, Secs).
+
+
+:- end_object.