>From f4d89b1c2984e5af94a26835e0be32dd15c03eae Mon Sep 17 00:00:00 2001
From: Florian Zumbiehl <address@hidden>
Date: Thu, 14 Mar 2013 05:43:46 +0100
Subject: [PATCH] alist-update: don't segfault on non-list

Check the lst argument for alist-update and alist-update! to be an
actual list.

Signed-off-by: Christian Kellermann <address@hidden>
---
 data-structures.scm |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/data-structures.scm b/data-structures.scm
index 56944ec..36f4dbf 100644
--- a/data-structures.scm
+++ b/data-structures.scm
@@ -198,6 +198,7 @@
 ;;; Alists:
 
 (define (alist-update! x y lst #!optional (cmp eqv?))
+  (##sys#check-list lst 'alist-update!)
   (let* ([aq (cond [(eq? eq? cmp) assq]
 		   [(eq? eqv? cmp) assv]
 		   [(eq? equal? cmp) assoc]
@@ -217,6 +218,7 @@
 	(cons (cons x y) lst) ) ) )
 
 (define (alist-update k v lst #!optional (cmp eqv?))
+  (##sys#check-list lst 'alist-update)
   (let loop ((lst lst))
     (if (null? lst)
         (list (cons k v))
-- 
1.7.6