Don't pass negative value to <ctype.h> functions.

1 files changed, 2 insertions, 2 deletions

diff --git a/autotab.c b/autotab.c
index 278c568..93c3500 100644
--- a/autotab.c
+++ b/autotab.c
@@ -256,14 +256,14 @@ static int fgrep(line_t *list, const char *pattern)
 
 int munge_char(int ch)
 {
+  if (ch < 0 || isalnum(ch) || ch == '_')
+    return TOKEN[0];
   if (isspace(ch) || iscntrl(ch))
     return SPACE[0];
   if (strchr("([{<", ch))
     return OPGRP[0];
   if (strchr(")]}>", ch))
     return CLGRP[0];
-  if (isalnum(ch) || ch == '_')
-    return TOKEN[0];
   return PUNCT[0];
 }