NOTE: As discussed in ../README, support for the current version of the simplify tool (which supersedes simplify-defun) may be found in community books directory books/kestrel/apt/. Supporting file for Section 2.1: example-producer-consumer.lisp Supporting file for Section 2.2: example-integers.lisp The remaining files support the definition of simplify-defun. To play with simplify-defun, evaluate the forms in simplify-defun-tests.lisp. Update, September 2021. Before now, community book kestrel/utilities/directed-untranslate.lisp supported the present directory's version of simplify-defun. But with this update, we have copied that version of directed-untranslate.lisp to the present directory and make simplify-defun.lisp depend on it, which allows future changes to kestrel/utilities/directed-untranslate.lisp without affecting the present directory. Because directed-untranslate.lisp includes make-executable.lisp, that was copied here as well.