Structures offer a way to store data in named slots. They support single inheritance. Classes provided by the Common Lisp Object System (CLOS) are more flexible however structures may offer better performance (see for example the SBCL manual). As usual, this is best read in the Common Lisp Cookbook. Structures Creation defstruct (defstruct person id name age) At creation slots are optional and default to nil. To set a default value:
