From 81ac5b999f1dae8bc821634dc3c3bc43239d8d65 Mon Sep 17 00:00:00 2001
From: colin <colin@cicadas.surf>
Date: Sat, 17 Aug 2024 21:19:18 -0700
Subject: Add: optional type

---
 package.lisp     | 1 +
 petty-types.lisp | 3 +++
 2 files changed, 4 insertions(+)

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))
-- 
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