Make is_set checking more explicit

If is_set is not one of the usual boolean values, return 2.

1 files changed, 3 insertions, 2 deletions

diff --git a/pm/functions.in b/pm/functions.in
index fab9b38..0aba5ea 100644
--- a/pm/functions.in
+++ b/pm/functions.in
@@ -8,8 +8,9 @@
 is_set()
 {
     case ${1-UNSET} in
-	[Tt][Rr][Uu][Ee]|[Yy][Ee][Ss]|1|'') return 0;;
-	*) return 1;;
+	true|yes|TRUE|YES|on|ON|1'') return 0;;
+	false|FALSE|no|NO|off|OFF|0|UNSET) return 1;;
+	*) return 2;;
     esac
 }