chickadee » type-extensions » list

(list . type)syntax
(list type ...)syntax

A dotted tail or ellipsis at the end of a list type form is shorthand for a sequence of pairs followed by (list-of type).

;; The following types are equivalent:
(define-type a (list fixnum float . number))
(define-type b (list fixnum float number ...))
(define-type c (pair fixnum (pair float (list-of number))))