Add an appendix on call-with-* style macros for later investigation

elisp-to-cl-lesson.org

@@ -2175,6 +2175,31 @@ Item 5 is ?
 (HOW DO YOU DO ?)
 #+end_src
 
+* [[http://random-state.net/log/3390120648.html][Why I like CALL-WITH-* style in macros]]
+:PROPERTIES:
+:CUSTOM_ID: sec:call-with-macros
+:END:
+
+Listing [[lst]] The post [[https://lists.gnu.org/archive/html/emacs-devel/2023-12/msg00683.html][João Távora: permanently fix org breakage during builds]]
+links to the origin of the code in listing [[lst:call-with-macros]].
+
+BUG: make a concrete ~CALL-WITH-*~ macro example.
+
+#+caption[Abstract "CALL-WITH-*" macro example]:
+#+caption: Abstract ~CALL-WITH-*~ macro example.
+#+caption: with variable clauses, exit clauses, and a body.
+#+name: lst:call-with-macros
+#+begin_src emacs-lisp -n :eval never
+(defmacro with-foo ((foo) &body body)
+  `(call-with-foo (lambda (,foo) ,@body)))
+
+(defun call-with-foo (function)
+  (let (foo)
+    (unwind-protect
+        (funcall function (setf foo (get-foo)))
+      (when foo (release-foo foo)))))
+#+end_src
+
 * Local variables                                                  :noexport:
 
 # Emacs looks for "Local variables:" after the last "newline-formfeed".