Add solution to p3

p3/regex.el

@@ -0,0 +1,34 @@
+(setq regex-1 ".*?mul(\\([[:digit:]]\\{1,3\\}\\),\\([[:digit:]]\\{1,3\\}\\))")
+
+(setq regex-2-1 ".*?\\(mul([[:digit:]]\\{1,3\\},[[:digit:]]\\{1,3\\})\\|don't()\\|do()\\)")
+
+(defun try-regex-part1 ()
+  (replace-regexp regex-1 "\n(* \\1 \\2);"))
+
+(defun try-regex-part2 ()
+  (interactive)
+  (goto-char (point-min))
+  (replace-regexp regex-2-1 "\n\\1") ;remove most of the broken code
+  (kill-line) ;remove the rest of the broken code
+  (goto-char (point-min))
+  (replace-regexp "do()" "do")
+  (goto-char (point-min))
+  (replace-regexp "don't()" "dont")
+  (goto-char (point-min))
+  (replace-regexp regex-1 "(* \\1 \\2)")
+    (goto-char (point-min))
+    (insert "(")
+    (goto-char (point-max))
+    (insert ")")
+  )
+
+;; the above turns the input into some pseudo lisp code. the code is then executed by the sexp below
+
+(-reduce-from (lambda (i e) (cond
+                             ((eq e 'do) `(t ,(cadr i)))
+                             ((eq e 'dont) `(nil ,(cadr i)))
+                             (t (if (car i) `(t ,(+ (cadr i) (eval e)))
+                                  `(t ,(cadr i))))))
+              '(t 0) code))
+
+; this is quite horrible, and probably there is a more efficient way