Recycle temporary list-of-lists in mapping functions.

* eval.c (mapcarv, mappendv, mapdov): When done, we can
recycle the conses used for the temporary copy of the
list-of-lists, whose car-s are used for iterating over the
lists in paralle. This is safe because the temporary
list's conses aren't shared with any other function.

1 files changed, 9 insertions, 3 deletions

diff --git a/eval.c b/eval.c
index 73eaf95b..7c8d9b45 100644
--- a/eval.c
+++ b/eval.c
@@ -3749,8 +3749,10 @@ val mapcarv(val fun, struct args *lists)
 
       for (iter = lofl; iter; iter = cdr(iter)) {
         val list = car(iter);
-        if (!list)
+        if (!list) {
+          rcyc_list(lofl);
           return make_like(out, list_orig);
+        }
         atail = list_collect(atail, car(list));
         deref(car_l(iter)) = cdr(list);
       }
@@ -3784,8 +3786,10 @@ static val mappendv(val fun, struct args *lists)
 
       for (iter = lofl; iter; iter = cdr(iter)) {
         val list = car(iter);
-        if (!list)
+        if (!list) {
+          rcyc_list(lofl);
           return make_like(out, list_orig);
+        }
         atail = list_collect(atail, car(list));
         deref(car_l(iter)) = cdr(list);
       }
@@ -3877,8 +3881,10 @@ static val mapdov(val fun, struct args *lists)
 
       for (iter = lofl; iter; iter = cdr(iter)) {
         val list = car(iter);
-        if (!list)
+        if (!list) {
+          rcyc_list(lofl);
           return nil;
+        }
         atail = list_collect(atail, car(list));
         deref(car_l(iter)) = cdr(list);
       }