From c357663f0a140dbd51b52c07b5175b2a9e3e38d4 Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Wed, 20 Mar 2019 22:56:33 -0400
Subject: [PATCH] Issue #310 - Fix type checking for member/assoc

---
 CHANGELOG.md | 5 +++++
 runtime.c    | 6 ++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f41e36f4..f905de73 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,8 +4,13 @@
 
 Features
 
+- Speed up `case` expressions by using nested `if` expressions instead of the `memv` primitive to evaluate conditions with more than one constant. The nested expressions have better cache locality and also avoid any additional object allocation or initialization.
 - Allow passing the `'bin` symbol to `Cyc-installation-dir` to return the location of the installation directory for binaries.
 
+Bug Fixes
+
+- Prevent the possibility of a segmentation fault when passing am improper list to the `member` and `assoc` family of functions.
+
 ## 0.9.10 - March 5, 2019
 
 Features
diff --git a/runtime.c b/runtime.c
index 5af65d43..7678fba6 100644
--- a/runtime.c
+++ b/runtime.c
@@ -1231,8 +1231,8 @@ object Cyc_write_u8(void *data, object c, object port)
 /* Fast versions of member and assoc */
 object memberp(void *data, object x, list l)
 {
-  Cyc_check_pair_or_null(data, l);
   for (; l != NULL; l = cdr(l)) {
+    Cyc_check_pair_or_null(data, l);
     if (boolean_f != equalp(x, car(l)))
       return l;
   }
@@ -1241,8 +1241,8 @@ object memberp(void *data, object x, list l)
 
 object memqp(void *data, object x, list l)
 {
-  Cyc_check_pair_or_null(data, l);
   for (; l != NULL; l = cdr(l)) {
+    Cyc_check_pair_or_null(data, l);
     if ((x == car(l)))
       return l;
   }
@@ -1254,6 +1254,7 @@ list assq(void *data, object x, list l)
   if ((l == NULL) || is_value_type(l) || type_of(l) != pair_tag)
     return boolean_f;
   for (; (l != NULL); l = cdr(l)) {
+    Cyc_check_pair(data, l);
     list la = car(l);
     Cyc_check_pair(data, la);
     if ((x == car(la)))
@@ -1267,6 +1268,7 @@ list assoc(void *data, object x, list l)
   if ((l == NULL) || is_value_type(l) || type_of(l) != pair_tag)
     return boolean_f;
   for (; (l != NULL); l = cdr(l)) {
+    Cyc_check_pair(data, l);
     list la = car(l);
     Cyc_check_pair(data, la);
     if (boolean_f != equalp(x, car(la)))