detected unmatched #if/#else/#endif

diff --git a/scripts/shader-cpp.sh b/scripts/shader-cpp.sh
index 28890ae3e9cd135fd22bc8af1f57870f93673938..4d0d4d85cdae3f323df79fd2c2cd00319ddec0cb 100755 (executable)
--- a/scripts/shader-cpp.sh
+++ b/scripts/shader-cpp.sh
@@ -7,6 +7,13 @@ case "$0" in
 esac
 
 . ./shader-parser.subr
+set -e
+
+err()
+{
+       echo >&2 "(EE) $*"
+       exit 1
+}
 
 LF="
 "
@@ -71,47 +78,58 @@ shaderkill()
 }
 preprocess()
 {
-       condstack=
-       echo "$shadertext" | while IFS= read -r L; do
-               [ -n "$L" ] || continue
-               set -- $L
-               k=$1
-               shift
-               case "$k" in
-                       '#if')
-                               case "$LF$conds$LF" in
-                                       *"$LF$*$LF"*)
-                                               condstack=0$condstack
-                                               ;;
-                                       *)
-                                               condstack=1$condstack
-                                               ;;
-                               esac
-                               ;;
-                       '#else')
-                               case "$condstack" in
-                                       0*)
-                                               condstack=1${condstack#0}
-                                               ;;
-                                       1*)
-                                               condstack=0${condstack#1}
-                                               ;;
-                               esac
-                               ;;
-                       '#endif')
-                               condstack=${condstack#?}
-                               ;;
-                       *)
-                               case "$condstack" in
-                                       *0*)
-                                               ;;
-                                       *)
-                                               echo "${L% }"
-                                               ;;
-                               esac
-                               ;;
-               esac
-       done
+       echo "$shadertext" | {
+               condstack=
+               while IFS= read -r L; do
+                       [ -n "$L" ] || continue
+                       set -- $L
+                       k=$1
+                       shift
+                       case "$k" in
+                               '#if')
+                                       case "$LF$conds$LF" in
+                                               *"$LF$*$LF"*)
+                                                       condstack=0$condstack
+                                                       ;;
+                                               *)
+                                                       condstack=1$condstack
+                                                       ;;
+                                       esac
+                                       ;;
+                               '#else')
+                                       if [ -z "$condstack" ]; then
+                                               err "unmatched #else"
+                                       fi
+                                       case "$condstack" in
+                                               0*)
+                                                       condstack=1${condstack#0}
+                                                       ;;
+                                               1*)
+                                                       condstack=0${condstack#1}
+                                                       ;;
+                                       esac
+                                       ;;
+                               '#endif')
+                                       if [ -z "$condstack" ]; then
+                                               err "unmatched #endif"
+                                       fi
+                                       condstack=${condstack#?}
+                                       ;;
+                               *)
+                                       case "$condstack" in
+                                               *0*)
+                                                       ;;
+                                               *)
+                                                       echo "${L% }"
+                                                       ;;
+                                       esac
+                                       ;;
+                       esac
+               done
+               if [ -n "$condstack" ]; then
+                       err "unmatched #if"
+               fi
+       }
 }
 conditionalize()
 {