[lib] add general purpose caching

lib/lib-advent.org

@@ -77,3 +77,14 @@
     (defmacro --2map-indexed (form li)
       `(-2map-indexed (lambda (it-index-1 it-index-2 it) ,form) ,li))
   #+end_src
+* general purpose caching
+ Add this function as an ~:around~ advice to any function to have its
+ results cached in ~cache~. The symbol ~cache~ should be already bound
+  #+begin_src emacs-lisp
+    (defun cache-result (fun &rest r)
+    (let ((c (assoc (cons fun r) cache)))
+      (if c (cdr c)
+        (let ((res (apply fun r)))
+    	(push (cons (cons fun r) res) cache)
+    	res ))))
+  #+end_src

p7/p7.org

@@ -74,12 +74,13 @@ Of course it will blow in my face if I did not cache the results
 #+begin_src emacs-lisp
   (setq max-lisp-eval-depth 10000000) ; burn baby burn
   (setq cache nil)
-  (defun cache-result (fun pos)
-    (let ((c (assoc pos cache)))
+  (defun cache-result (fun &rest r)
+    (let ((c (assoc (cons fun r) cache)))
       (if c (cdr c)
-        (let ((res (funcall fun pos)))
-    	(push (cons pos res) cache)
+        (let ((res (apply fun r)))
+    	(push (cons (cons fun r) res) cache)
     	res ))))
+  
 (advice-add 'timelines-at :around 'cache-result)
 
   (defun timelines-at (pos)
@@ -95,3 +96,5 @@ Of course it will blow in my face if I did not cache the results
 
 #+RESULTS:
 : 1537373473728
+
+