Logtalk 2.25.0 files.

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1288 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

Logtalk/examples/diamonds/NOTES

@@ -1,6 +1,6 @@
 =================================================================
 Logtalk - Object oriented extension to Prolog
-Release 2.24.0
+Release 2.25.0
 
 Copyright (c) 1998-2005 Paulo Moura.  All Rights Reserved.
 =================================================================

Logtalk/examples/diamonds/SCRIPT

@@ -1,6 +1,6 @@
 =================================================================
 Logtalk - Object oriented extension to Prolog
-Release 2.24.0
+Release 2.25.0
 
 Copyright (c) 1998-2005 Paulo Moura.  All Rights Reserved.
 =================================================================
@@ -12,7 +12,7 @@ Copyright (c) 1998-2005 Paulo Moura.  All Rights Reserved.
 ...
 
 
-% first variant of the "diamond problem", defined in the "diamond1" metafile:
+% first variant of the "diamond problem", defined in the "diamond1" source file:
 
 | ?- d1::m.
 
@@ -20,7 +20,7 @@ Redefinition of method m/0 in object b1
 yes
 
 
-% second variant of the "diamond problem", defined in the "diamond2" metafile:
+% second variant of the "diamond problem", defined in the "diamond2" source file:
 
 | ?- d2::m.
 
@@ -28,7 +28,7 @@ Redefinition of method m/0 in object c2
 yes
 
 
-% third variant of the "diamond problem", defined in the "diamond3" metafile:
+% third variant of the "diamond problem", defined in the "diamond3" source file:
 
 | ?- d3::b3_m.
 

Logtalk/examples/diamonds/diamond1.lgt

@@ -0,0 +1,57 @@
+/*
+These objects illustrate a variant of the "diamond problem" using 
+a prototype hierarchy.
+
+In this simple case, the inherited definition which will be used in the  
+bottom object is determined by the Logtalk predicate lookup algorithm. 
+*/
+
+
+% root object, declaring and defining a predicate m/0:
+
+:- object(a1).
+
+	:- public(m/0).
+
+	m :-
+		this(This),
+		write('Default definition of method m/0 in object '),
+		write(This), nl.
+
+:- end_object.
+
+
+% an object descending from the root object, which redefines predicate m/0:
+
+:- object(b1,
+	extends(a1)).
+
+	m :-
+		this(This),
+		write('Redefinition of method m/0 in object '),
+		write(This), nl.
+
+:- end_object.
+
+
+% another object descending from the root object, which also redefines predicate m/0:
+
+:- object(c1,
+	extends(a1)).
+
+	m :-
+		this(This),
+		write('Redefinition of method m/0 in object '),
+		write(This), nl.
+
+:- end_object.
+
+
+% bottom object, descending from the two previous objects and, as such, inheriting
+% two definitions for the predicate m/0:
+
+:- object(d1,
+	extends(b1, c1)).
+
+
+:- end_object.

Logtalk/examples/diamonds/diamond2.lgt

@@ -0,0 +1,64 @@
+/*
+These objects illustrate a variant of the "diamond problem" using 
+a prototype hierarchy.
+
+In this simple case, a solution for making the overridden definition inherited 
+by the bottom object the visible one is implemented using the alias/3 predicate 
+directive. 
+*/
+
+
+% root object, declaring and defining a predicate m/0:
+
+:- object(a2).
+
+	:- public(m/0).
+
+	m :-
+		this(This),
+		write('Default definition of method m/0 in object '),
+		write(This), nl.
+
+:- end_object.
+
+
+% an object descending from the root object, which redefines predicate m/0:
+
+:- object(b2,
+	extends(a2)).
+
+	m :-
+		this(This),
+		write('Redefinition of method m/0 in object '),
+		write(This), nl.
+
+:- end_object.
+
+
+% another object descending from the root object, which also redefines predicate m/0:
+
+:- object(c2,
+	extends(a2)).
+
+	m :-
+		this(This),
+		write('Redefinition of method m/0 in object '),
+		write(This), nl.
+
+:- end_object.
+
+
+% bottom object, descending from the two previous objects and, as such, inheriting
+% two definitions for the predicate m/0; the overridden definition inherited from 
+% object "c2" is renamed using the alias/3 directive and then we redefine the 
+% predicate m/0 to call the renamed definition:
+
+:- object(d2,
+	extends(b2, c2)).
+
+	:- alias(c2, m/0, c2_m/0).
+	
+	m :-
+		::c2_m.
+
+:- end_object.

Logtalk/examples/diamonds/diamond3.lgt

@@ -0,0 +1,61 @@
+/*
+These objects illustrate a variant of the "diamond problem" using 
+a prototype hierarchy.
+
+In this simple case, a solution is presented for making two conflicting 
+definitions inherited by the bottom object visible through the use of the 
+alias/3 predicate directive. 
+*/
+
+
+% root object, declaring and defining a predicate m/0:
+
+:- object(a3).
+
+	:- public(m/0).
+
+	m :-
+		this(This),
+		write('Default definition of method m/0 in object '),
+		write(This), nl.
+
+:- end_object.
+
+
+% an object descending from the root object, which redefines predicate m/0:
+
+:- object(b3,
+	extends(a3)).
+
+	m :-
+		this(This),
+		write('Redefinition of method m/0 in object '),
+		write(This), nl.
+
+:- end_object.
+
+
+% another object descending from the root object, which also redefines predicate m/0:
+
+:- object(c3,
+	extends(a3)).
+
+	m :-
+		this(This),
+		write('Redefinition of method m/0 in object '),
+		write(This), nl.
+
+:- end_object.
+
+
+% bottom object, descending from the two previous objects and, as such, inheriting
+% two definitions for the predicate m/0; both inherited definitions are renamed 
+% using the alias/3 directive:
+
+:- object(d3,
+	extends(b3, c3)).
+
+	:- alias(b3, m/0, b3_m/0).
+	:- alias(c3, m/0, c3_m/0).
+
+:- end_object.