From 310d8d21bfc8a024c9a469a1f39a2370008fd9ea Mon Sep 17 00:00:00 2001
From: Yann Herklotz <git@yannherklotz.com>
Date: Wed, 22 Dec 2021 18:34:27 +0100
Subject: Add day 5 to aoc

---
 src/common.lisp | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'src/common.lisp')

diff --git a/src/common.lisp b/src/common.lisp
index 2c56184..c9e6e8b 100644
--- a/src/common.lisp
+++ b/src/common.lisp
@@ -15,3 +15,8 @@
 (defun trim (input)
   (string-trim '(#\Space #\Newline #\Backspace #\Tab
                  #\Linefeed #\Page #\Return #\Rubout) input))
+
+(defun fold-left (reducer initial list)
+  (loop for fold = initial then (funcall reducer fold element)
+        for element in list
+        finally (return fold)))
-- 
cgit