# Executing multiple statements with if/cond (Lisp)

 P: 39 To answer the original question, assuming Common Lisp, you want to use prog (short for "program"), or its variations depending which value you want returned. For example: (if (zerop index) nil (progn (first-form) (second-form))) That example uses the progn variation of prog. It will evaluate all the contained forms in order and yield the value of last one (second-form in this case). progn is probably the most common way of evaluating multiple forms. Then there's prog1 and prog2, which behave similarly except they yield the first or second value rather than the last. Many other forms such as when and unless have implicit progn, so you can do something like: (unless (zerop index) (first-form) (second-form)) If you want to learn the basics of Common Lisp, I suggest you read Practical Common Lisp by Peter Seibel. It's free online.