use call-with-input-file

day-2.scm

@@ -5,39 +5,41 @@
 	(list->string (reverse w))
 	(loop (cons c w))))))
 
-(let [(file (open-input-file "day-2.input"))]
-  (let loop [(x 0) (y 0)]
-    (let [(amount (string->number (get-word file)))
-	  (move (get-word file))]
-      (cond
-	((string=? move "forward")
-	 (loop (+ x amount) y))
-	((string=? move "down")
-	 (loop x (+ y amount)))
-	((string=? move "up")
-	 (loop x (- y amount)))
-	(else
-	  (display "part 1: ")
-	  (display (* x y))
-	  (newline)
-	  (close-port file))))))
+(call-with-input-file
+  "day-2.input"
+  (lambda (file)
+    (let loop [(x 0) (y 0)]
+      (let [(amount (string->number (get-word file)))
+	    (move (get-word file))]
+	(cond
+	  ((string=? move "forward")
+	   (loop (+ x amount) y))
+	  ((string=? move "down")
+	   (loop x (+ y amount)))
+	  ((string=? move "up")
+	   (loop x (- y amount)))
+	  (else
+	    (display "part 1: ")
+	    (display (* x y))
+	    (newline)))))))
 
-(let [(file (open-input-file "day-2.input"))]
-  (let loop [(x 0) (y 0) (aim 0)]
-    (let [(amount (string->number (get-word file)))
-	  (move (get-word file))]
-      (cond
-	((string=? move "forward")
-	 (loop 
-	   (+ x amount) 
-	   (+ y (* aim amount))
-	   aim))
-	((string=? move "down")
-	 (loop x y (+ aim amount)))
-	((string=? move "up")
-	 (loop x y (- aim amount)))
-	(else
-	  (display "part 2: ")
-	  (display (* x y))
-	  (newline)
-	  (close-port file))))))
+(call-with-input-file
+  "day-2.input"
+  (lambda (file)
+    (let loop [(x 0) (y 0) (aim 0)]
+      (let [(amount (string->number (get-word file)))
+	    (move (get-word file))]
+	(cond
+	  ((string=? move "forward")
+	   (loop 
+	     (+ x amount) 
+	     (+ y (* aim amount))
+	     aim))
+	  ((string=? move "down")
+	   (loop x y (+ aim amount)))
+	  ((string=? move "up")
+	   (loop x y (- aim amount)))
+	  (else
+	    (display "part 2: ")
+	    (display (* x y))
+	    (newline)))))))