34892 (slightly tweaked): math evaluation fix

An empty expression resulting from substitution includes a
Nularg, which needs handling the same as an empty string.

1 files changed, 2 insertions, 2 deletions

diff --git a/Src/math.c b/Src/math.c
index c047725c5..2105180c8 100644
--- a/Src/math.c
+++ b/Src/math.c
@@ -1398,7 +1398,7 @@ matheval(char *s)
     if (!mlevel)
 	outputradix = outputunderscore = 0;
 
-    if (!*s) {
+    if (!*s || *s == Nularg) {
 	x.type = MN_INTEGER;
 	x.u.l = 0;
 	return x;
@@ -1435,7 +1435,7 @@ mathevalarg(char *s, char **ss)
      *
      * To avoid a more opaque error further in, bail out here.
      */
-    if (!*s) {
+    if (!*s || *s == Nularg) {
 	zerr("bad math expression: empty string");
 	return (zlong)0;
     }