X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fearly-type.lisp;h=53137bacba2d2b04c1ba8a13b60457c90c0f2f66;hb=f3f1143a09fa2e50eec13614cc6b0306b2b11fad;hp=56aac8c3691dcd7559e3d95baa2359e6ec653be7;hpb=d3c56c291d4d4eff8c3ec234d5ed904fe5b55df4;p=sbcl.git

diff --git a/src/code/early-type.lisp b/src/code/early-type.lisp
index 56aac8c..53137ba 100644
--- a/src/code/early-type.lisp
+++ b/src/code/early-type.lisp
@@ -460,6 +460,24 @@
 	  (eq cdr-type *empty-type*))
       *empty-type*
       (%make-cons-type car-type cdr-type)))
+
+(defun cons-type-length-info (type)
+  (declare (type cons-type type))
+  (do ((min 1 (1+ min))
+       (cdr (cons-type-cdr-type type) (cons-type-cdr-type cdr)))
+      ((not (cons-type-p cdr))
+       (cond
+	 ((csubtypep cdr (specifier-type 'null))
+	  (values min t))
+	 ((csubtypep *universal-type* cdr)
+	  (values min nil))
+	 ((type/= (type-intersection (specifier-type 'cons) cdr) *empty-type*)
+	  (values min nil))
+	 ((type/= (type-intersection (specifier-type 'null) cdr) *empty-type*)
+	  (values min t))
+	 (t (values min :maybe))))
+    ()))
+       
 
 ;;;; type utilities