Solve part 2 of Not Quite Lisp

Solving the first question of Advent Of Code 2015 \o/

2015/days/01/lisp.lisp

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+;; Day 1: Not Quite Lisp
+;;
+;; Part 1: What is the floor Santa takes ?
+
+
+(defparameter balance 0)
+
+(defun direction (char) (cond
+                           ((char= char #\()
+                            +1)
+                           ((char= char #\))
+                            -1)
+                        ))
+
+(with-open-file (in "./data/input")
+
+  (do ((char (read-char in nil)
+             (read-char in nil)))
+      ((null char))
+    (setf balance (+ balance (direction char)))))
+
+(print balance)

2015/days/01/lisp2.lisp

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+;; Day 1: Not Quite Lisp
+;;
+;; Part 2: Position of the character with balance -1 (basement)
+;;
+;; ref.
+;; - read: https://lispcookbook.github.io/cl-cookbook/files.html
+
+(defparameter balance 0)
+(defparameter position 0)
+
+(defun direction (char) (cond
+                           ((char= char #\()
+                            +1)
+                           ((char= char #\))
+                            -1)
+                        ))
+
+(with-open-file (in "./data/input")
+  (loop for char = (read-char in nil)
+        until (= balance -1)
+        do
+       (setf balance
+             (+ balance (direction char)))
+       (setf position
+             (+ position 1))))
+
+(print position)