diff options
-rw-r--r-- | package.lisp | 1 | ||||
-rw-r--r-- | petty-types.lisp | 3 |
2 files changed, 4 insertions, 0 deletions
diff --git a/package.lisp b/package.lisp index 57ed987..6472436 100644 --- a/package.lisp +++ b/package.lisp @@ -6,5 +6,6 @@ (#:a #:alexandria-2)) (:export #:type-specifier-p ; function + #:optional ; deftype #:vector-of ; deftype #:list-of)) ; deftype diff --git a/petty-types.lisp b/petty-types.lisp index 1d092b9..994f2e9 100644 --- a/petty-types.lisp +++ b/petty-types.lisp @@ -41,3 +41,6 @@ "Type specifier for vectors all of the same TYPE." `(satisfies ,(sequence-of-predicate-for 'vector type len))) +(deftype optional (type) + "Type specifier for an optional type." + `(or null ,type)) |