Fixato cancellazione definizione di `this`

diff --git a/Prolog/README.org b/Prolog/README.org
index b23a6f2df5e7f21d1584c45b62e8ec8df9d0e84d..5facf4d88c2e08e31748c9eeac1aa157c5d5225d 100644 (file)
--- a/Prolog/README.org
+++ b/Prolog/README.org
@@ -1,5 +1,8 @@
 #+title: 💀 OOΠ in Prolog 💀
-#+author: Bizzoni Leonardo (899629), Barone Matteo(894594), Kier Mirko Tolentino(899728)
+#+author: Bizzoni Leonardo (899629),
+#+author: Barone Matteo(894594),
+#+author: Kier Mirko Tolentino(899728)
+#+options: TOC:nil
 
 * Breve descrizione
 42
@@ -60,18 +63,22 @@ def_class(ClassName, Parents, Parts) :-
 *** Esempio pratico
 #+name: def_class
 #+begin_src prolog
-def_class(foo, [], [field(foo, 42), method(foo, [Number], (field(this, foo, Foo),
-                                                            Sum is Number + Foo,
-                                                            write("Sum: "), writeln(Sum)))]).
-
-def_class(bar, [], [field(bar, "42"), method(bar, [], (write("Favorite number is "),
-                                                        field(this, bar, Bar),
-                                                        writeln(Bar)))]).
-
-def_class(foobar, [foo, bar], [field(foobar, "Baz"), method(foobar, [X, X, [X]], (!)), method(foobar, [Start, End, [Start | Ls]], (Start =< End,
-                                                                                                                                    N is Start + 1,
-                                                                                                                                    foobar(this, N, End, Ls)))]).
-
+def_class(foo, [], [field(foo, 42),
+                   method(foo, [Number], (field(this, foo, Foo),
+                                          Sum is Number + Foo,
+                                          write("Sum: "), writeln(Sum)))]).
+
+def_class(bar, [], [field(bar, "42"),
+                   method(bar, [], (write("Favorite number is "),
+                                    field(this, bar, Bar),
+                                    writeln(Bar)))]).
+
+def_class(foobar, [foo, bar], [field(foobar, "Baz"),
+                              method(foobar, [X, X, [X]], (!)),
+                              method(foobar, [Start, End, [Start | Ls]],
+                                     (Start =< End,
+                                      N is Start + 1,
+                                      foobar(this, N, End, Ls)))]).
 #+end_src
 ** make
 *** Definizione
@@ -165,7 +172,7 @@ fieldx(Instance, [FieldName], Res) :-
     !.
 fieldx(Instance, [FieldName | Others], Res) :-
     is_instance(Instance),
-    field(Instance, FieldName, Value),
+    field(Instance, FieldName, _Value),
     fieldx(Instance, Others, Res).
 #+end_src
 
@@ -288,16 +295,25 @@ check_fields(InstanceName, [=(Field, Value) | Other]) :-
 
 ** define_this
 #+begin_src prolog :tangle oop.pl
-define_this(Instance) :-
+define_this(Instance, For) :-
     \+ is_list(Instance),
     !,
     findall(Key = Value, field(Instance, Key, Value), List),
-    define_this(List).
+    define_this(List, For).
 
-define_this([]) :- !.
-define_this([=(Key, Value) | Other]) :-
+define_this([], []) :- !.
+define_this([=(Key, Value) | Other], [Key | Rest]) :-
     asserta(field(this, Key, Value)),
-    define_this(Other).
+    define_this(Other, Rest).
+#+end_src
+
+** undefine_this
+#+begin_src prolog :tangle oop.pl
+undefine_this([]) :- !.
+undefine_this([FieldName | Other]) :-
+    retract(field(this, FieldName, _Value)),
+    !,
+    undefine_this(Other).
 #+end_src
 
 ** call_method
@@ -305,10 +321,10 @@ define_this([=(Key, Value) | Other]) :-
 call_method(Instance, ClassName, Body) :-
     is_instance(Instance, ClassName),
     asserta(is_instance(this, ClassName)),
-    define_this(Instance),
+    define_this(Instance, For),
     call_cleanup(call(Body), (
                     retractall(is_instance(this, ClassName)),
-                    retractall(field(this, _, _)))).
+                    undefine_this(For))).
 #+end_src
 
 ** check_value_type

diff --git a/Prolog/oop.pl b/Prolog/oop.pl
index 3ec30c9a6a94b65aa8ca89c34a64ff4af73abc13..9b2c415c39f8d72977194540c3fb1fe9ed41beb9 100644 (file)
--- a/Prolog/oop.pl
+++ b/Prolog/oop.pl
@@ -95,7 +95,7 @@ fieldx(Instance, [FieldName], Res) :-
     !.
 fieldx(Instance, [FieldName | Others], Res) :-
     is_instance(Instance),
-    field(Instance, FieldName, Value),
+    field(Instance, FieldName, _Value),
     fieldx(Instance, Others, Res).
 
 :- dynamic is_class/1.
@@ -194,24 +194,30 @@ check_fields(InstanceName, [=(Field, Value) | Other]) :-
     field(InstanceName, Field, Value),
     check_fields(InstanceName, Other).
 
-define_this(Instance) :-
+define_this(Instance, For) :-
     \+ is_list(Instance),
     !,
     findall(Key = Value, field(Instance, Key, Value), List),
-    define_this(List).
+    define_this(List, For).
 
-define_this([]) :- !.
-define_this([=(Key, Value) | Other]) :-
+define_this([], []) :- !.
+define_this([=(Key, Value) | Other], [Key | Rest]) :-
     asserta(field(this, Key, Value)),
-    define_this(Other).
+    define_this(Other, Rest).
+
+undefine_this([]) :- !.
+undefine_this([FieldName | Other]) :-
+    retract(field(this, FieldName, _Value)),
+    !,
+    undefine_this(Other).
 
 call_method(Instance, ClassName, Body) :-
     is_instance(Instance, ClassName),
     asserta(is_instance(this, ClassName)),
-    define_this(Instance),
+    define_this(Instance, For),
     call_cleanup(call(Body), (
                     retractall(is_instance(this, ClassName)),
-                    retractall(field(this, _, _)))).
+                    undefine_this(For))).
 
 check_value_type(nil, _X) :- !.
 check_value_type(var, X) :- var(X), !.