From: kier-mirko <mirkotolentino1@gmail.com>
Date: Tue, 2 Jan 2024 09:59:09 +0000 (+0100)
Subject: Aggiunto field e field*
X-Git-Url: http://git.leonardobizzoni.com/?a=commitdiff_plain;h=7305e23e0cf7ae43a8c086fc2bddb9b320f58210;p=ObjectOriented-Prolog-Lisp

Aggiunto field e field*
---

diff --git a/Lisp/README.org b/Lisp/README.org
index b86bfd8..84fa528 100644
--- a/Lisp/README.org
+++ b/Lisp/README.org
@@ -60,9 +60,15 @@
 ** field
 *** Definizione
 
-
 *** Implementazione
 #+begin_src lisp :tangle ool.lisp
+(defun field (instance field-name)
+  (field-helper (getf instance :fields) field-name))
+
+(defun field-helper (fields field-name)
+  (cond ((null fields) nil)
+	((eq (caar fields) field-name) (cadar fields))
+	(T (field-helper (cdr fields) field-name))))
 #+end_src
 
 *** Esempio pratico
@@ -73,6 +79,11 @@
 
 *** Implementazione
 #+begin_src lisp :tangle ool.lisp
+(defun field* (instance fields)
+  (cond ((null fields) nil)
+	((null (cdr fields)) (field instance (car fields)))
+	((null (field instance (car fields))) nil)
+	(T (field* instance (cdr fields)))))
 #+end_src
 
 *** Esempio pratico
diff --git a/Lisp/ool.lisp b/Lisp/ool.lisp
index f1878c7..c16e33b 100644
--- a/Lisp/ool.lisp
+++ b/Lisp/ool.lisp
@@ -30,9 +30,19 @@
      (create-instance instance fields))
    (copy-list (class-spec classname))))
 
+(defun field (instance field-name)
+  (field-helper (getf instance :fields) field-name))
 
+(defun field-helper (fields field-name)
+  (cond ((null fields) nil)
+	((eq (caar fields) field-name) (cadar fields))
+	(T (field-helper (cdr fields) field-name))))
 
-
+(defun field* (instance fields)
+  (cond ((null fields) nil)
+	((null (cdr fields)) (field instance (car fields)))
+	((null (field instance (car fields))) nil)
+	(T (field* instance (cdr fields)))))
 
 (defparameter *classes-specs* (make-hash-table))