added back short examples in code_snippets_for_book

mark-watson · mark-watson · commit fdcaadb4c850 · 2025-11-03T13:25:10.000-07:00
diff --git a/manuscript/input_output.md b/manuscript/input_output.md
@@ -56,7 +56,7 @@ In this last example, we passed the file name as a string to the macro **with-op
           (make-pathname :directory "testdata"
                          :name "test.dat")))
     (with-open-file
-     (input-stream a-path-name :direction :input)
+     (input-stream a-path-name :direction :input)))
 ~~~~~~~~
 
 Here, we are specifying that we want to use the file **test.dat** in the subdirectory **testdata**. Note: I almost never use pathnames. Instead, I specify files using a string and the character / as a directory delimiter. I find this to be portable for the Macintosh, Windows, and Linux operating systems using all Common Lisp implementations.
diff --git a/src/code_snippets_for_book/nested.lisp b/src/code_snippets_for_book/nested.lisp
@@ -0,0 +1,31 @@
+(flet ((add-one (x)
+         (+ x 1))
+       (add-two (x)
+         (+ x 2)))
+  (format t "redefined variables: ~A  ~A~%" (add-one 100) (add-two 100)))
+
+(let ((a 3.14))
+  (defun test2 (x) ; this works, but don't do it!
+    (print x))
+  (test2 a))
+
+(test2 50)
+
+(let ((x 1)
+      (y 2))
+  ;; properly define a test function nested inside a let statement:
+  (flet ((test (a b)
+           (let ((z (+ a b)))
+             ;; define a helper function nested inside a let/function/let:
+             (flet ((nested-function (a)
+                      (+ a a)))
+               (nested-function z)))))
+    ;; call nested function 'test':
+    (format t "test result is ~A~%" (test x y))))
+
+(let ((z 10))
+  (labels ((test-recursion (a)
+             (format t "test-recursion ~A~%" (+ a z))
+             (if (> a 0)
+                 (test-recursion (- a 1)))))
+    (test-recursion 5)))
diff --git a/src/code_snippets_for_book/read-from-string-test.lisp b/src/code_snippets_for_book/read-from-string-test.lisp
@@ -0,0 +1,9 @@
+(defun read-from-string-test ()
+  "read a maximum of 1000 expressions from a string"
+  (let ((str "1 2 \"My parrot is named Brady.\" (11 22)"))
+    (with-input-from-string
+     (input-stream str)
+     (dotimes (i 1000)
+       (let ((x (read input-stream nil nil)))
+         (if (null x) (return)) ;; break out of the 'dotimes' loop
+         (format t "next expression in string: ~S~%" x))))))
diff --git a/src/code_snippets_for_book/read-test-1.lisp b/src/code_snippets_for_book/read-test-1.lisp
@@ -0,0 +1,8 @@
+(defun read-test-1 ()
+  "read a maximum of 1000 expressions from the file 'test.dat'"
+  (with-open-file
+   (input-stream "test.dat" :direction :input)
+   (dotimes (i 1000)
+     (let ((x (read input-stream nil nil)))
+       (if (null x) (return)) ;; break out of the 'dotimes' loop
+       (format t "next expression in file: ~S~%" x)))))
diff --git a/src/code_snippets_for_book/read-test-2.lisp b/src/code_snippets_for_book/read-test-2.lisp
@@ -0,0 +1,5 @@
+(let ((a-path-name
+          (make-pathname :directory "testdata"
+                         :name "test.dat")))
+    (with-open-file
+     (input-stream a-path-name :direction :input)))
diff --git a/src/code_snippets_for_book/readline-test.lisp b/src/code_snippets_for_book/readline-test.lisp
@@ -0,0 +1,8 @@
+(defun readline-test ()
+  "read a maximum of 1000 expressions from the file 'test.dat'"
+  (with-open-file
+   (input-stream "test.dat" :direction :input)
+   (dotimes (i 1000)
+     (let ((x (read-line input-stream nil nil)))
+       (if (null x) (return)) ;; break out of the 'dotimes' loop
+       (format t "next line in file: ~S~%" x)))))
diff --git a/src/code_snippets_for_book/test.dat b/src/code_snippets_for_book/test.dat
@@ -0,0 +1,2 @@
+1 2 3
+4 "the cat bit the rat"
