--- a/plcopen/structures.py	Mon Oct 24 02:03:42 2011 +0200
+++ b/plcopen/structures.py	Mon Oct 24 02:06:34 2011 +0200
@@ -639,10 +639,10 @@
 
 
 # Keywords for Structured Text
-ST_KEYWORDS = ["TRUE", "FALSE", "IF", "THEN", "ELSIF", "ELSE", "END_IF", "CASE", "OF", "END_CASE", 
- "FOR", "TO", "BY", "DO", "END_FOR", "WHILE", "DO", "END_WHILE", "REPEAT", "UNTIL", 
- "END_REPEAT", "EXIT", "RETURN", "NOT", "MOD", "AND", "XOR", "OR"]
-
+ST_BLOCK_START_KEYWORDS = ["IF", "ELSIF", "ELSE", "CASE", "FOR", "WHILE", "REPEAT"]
+ST_BLOCK_END_KEYWORDS = ["END_IF", "END_CASE", "END_FOR", "END_WHILE", "END_REPEAT"]
+ST_KEYWORDS = ["TRUE", "FALSE", "THEN", "OF", "TO", "BY", "DO", "DO", "UNTIL", "EXIT", 
+ "RETURN", "NOT", "MOD", "AND", "XOR", "OR"] + ST_BLOCK_START_KEYWORDS + ST_BLOCK_END_KEYWORDS
 
 # All the keywords of IEC
 IEC_KEYWORDS = ["E", "TRUE", "FALSE"]