From 0551a6fd4cfd90466fd6e35eb1e00d31257faf3e Mon Sep 17 00:00:00 2001
From: "Elf M. Sternberg" <elf.sternberg@gmail.com>
Date: Wed, 13 May 2015 22:23:30 -0700
Subject: [PATCH] Chapter 3 stub.

---
 chap3.rkt | 10 ++++++++++
 1 file changed, 10 insertions(+)
 create mode 100644 chap3.rkt

diff --git a/chap3.rkt b/chap3.rkt
new file mode 100644
index 0000000..c1c42a9
--- /dev/null
+++ b/chap3.rkt
@@ -0,0 +1,10 @@
+(define (find-symbol id tree)
+  (call/cc
+   (lambda (exit) 
+     (define (find tree)
+       (if (pair? tree)
+           (or (find (car tree)) (find (cdr tree)))
+           (if (eq? tree id) (exit #t) #f)))
+     (find tree))))
+           
+