From c054cf39a062f9eb377acaa84626bfb7f9b7fe4a Mon Sep 17 00:00:00 2001
From: Joel Chippindale <joel@joelchippindale.com>
Date: Mon, 28 Apr 2014 19:14:59 +0100
Subject: [PATCH] Implement `or`

---
 lib/list.rb | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/list.rb b/lib/list.rb
index 787126b..1f4c302 100644
--- a/lib/list.rb
+++ b/lib/list.rb
@@ -24,6 +24,8 @@ def evaluate(env)
           arguments.first
         when :cond
           arguments.detect { |list| list.car.evaluate(env) == Atom::TRUE }.cdr.car.evaluate(env)
+        when :or
+          arguments.first.evaluate(env) == Atom::TRUE ? Atom::TRUE : arguments.last.evaluate(env)
         else
           first_argument, *other_arguments = arguments.map { |a| a.evaluate(env) }
           first_argument.send(operation, *other_arguments)