pulled in lisp koans for solving

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

lisp-koans/koans/backquote.lisp

@@ -0,0 +1,65 @@
+;;; 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.
+
+;;; Backquote notation is similar to quoting, except it allows for parts of the
+;;; resulting expression to be "unquoted".
+
+(define-test backquote-basics
+  (let ((x '(123))
+        (z '(7 8 9)))
+    ;; ' quotes an expression normally.
+    (assert-equal ____ '(x 45 6 z))
+    ;; ` backquotes an expression; without any unquotes, it is equivalent to
+    ;; using the normal quote.
+    (assert-equal ____ `(x 45 6 z))
+    ;; , unquotes a part of the expression.
+    (assert-equal ____ `(,x 45 6 z))
+    (assert-equal ____ `(,x 45 6 ,z))
+    ;; ,@ splices an expression into the into the list surrounding it.
+    (assert-equal ____ `(,x 45 6 ,@z))
+    (assert-equal ____ `(,@x 45 6 ,@z))))
+
+(define-test backquote-forms
+  ;; Because of its properties, backquote is useful for constructing Lisp forms
+  ;; that are macroexpansions or parts of macroexpansions.
+  (let ((variable 'x))
+    ;; Fill in the blank without without using backquote/unquote notation.
+    (assert-equal ____
+                  `(if (typep ,variable 'string)
+                       (format nil "The value of ~A is ~A" ',variable ,variable)
+                       (error 'type-error :datum ,variable
+                                          :expected-type 'string))))
+  (let ((error-type 'type-error)
+        (error-arguments '(:datum x :expected-type 'string)))
+    ;; Fill in the blank without without using backquote/unquote notation.
+    (assert-equal ____
+                  `(if (typep x 'string)
+                       (format nil "The value of ~A is ~A" 'x x)
+                       (error ',error-type ,@error-arguments)))))
+
+(define-test numbers-and-words
+  (let ((number 5)
+        (word 'dolphin))
+    (true-or-false? ____ (equal '(1 3 5) `(1 3 5)))
+    (true-or-false? ____ (equal '(1 3 5) `(1 3 number)))
+    (assert-equal ____ `(1 3 ,number))
+    (assert-equal _____ `(word ,word ,word word))))
+
+(define-test splicing
+  (let ((axis '(x y z)))
+    (assert-equal '(the axis are ____) `(the axis are ,axis))
+    (assert-equal '(the axis are ____) `(the axis are ,@axis)))
+  (let ((coordinates '((43.15 77.6) (42.36 71.06))))
+    (assert-equal ____ `(the coordinates are ,coordinates))
+    (assert-equal ____ `(the coordinates are ,@coordinates))))