pulled in lisp koans for solving

https://github.com/google/lisp-koans

lisp-koans/koans-solved/scope-and-extent.lisp

@@ -0,0 +1,48 @@
+;;; Copyright 2013 Google Inc.
+;;;
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
+;;;
+;;;     http://www.apache.org/licenses/LICENSE-2.0
+;;;
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
+
+(define-test shadowing
+  (assert-equal '(4 2) (let ((z 4)) (list z (let ((z 2)) z)))))
+
+(defun block-1 ()
+  (block here
+    (return-from here 4)
+    5))
+
+(defun block-2 ()
+  (block outer
+    (block inner
+      (return-from outer 'space)
+      (return-from inner 'tube))
+    (return-from outer 'valve)))
+
+(define-test block-return-from
+  (assert-equal 4 (block-1))
+  (assert-equal 'space (block-2)))
+
+;;; See http://www.gigamonkeys.com/book/variables.html
+
+(define-test lexical-variables-can-be-enclosed
+  (assert-equal 10 (let ((f (let ((x 10))
+                              (lambda () x))))
+                     (let ((x 20))
+                       (funcall f)))))
+
+(define-test dynamic-variables-are-affected-by-execution-path
+  (assert-equal 20 (let ((f (let ((x 10))
+                              (declare (special x))
+                              (lambda () x))))
+                     (let ((x 20))
+                       (declare (special x))
+                       (funcall f)))))