From 23f32e98a31fa5df4390d28817f851a9984f6fee Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Wed, 17 May 2006 19:48:05 +0100
Subject: [PATCH] base: Export unsigned-fixnum as a handy type to have.

---
 mdw-base.lisp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/mdw-base.lisp b/mdw-base.lisp
index e87c511..c4c3e17 100644
--- a/mdw-base.lisp
+++ b/mdw-base.lisp
@@ -28,7 +28,8 @@
 
 (defpackage #:mdw.base
   (:use #:common-lisp)
-  (:export #:compile-time-defun
+  (:export #:unsigned-fixnum
+	   #:compile-time-defun
 	   #:show
 	   #:stringify #:mappend #:listify #:fix-pair #:pairify #:parse-body
 	   #:whitespace-char-p
@@ -44,6 +45,13 @@
 (in-package #:mdw.base)
 
 ;;;--------------------------------------------------------------------------
+;;; Useful types.
+
+(deftype unsigned-fixnum ()
+  "Unsigned fixnums; useful as array indices and suchlike."
+  `(mod ,most-positive-fixnum))
+
+;;;--------------------------------------------------------------------------
 ;;; Some simple macros to get things going.
 
 (defmacro compile-time-defun (name args &body body)
-- 
2.11.0