--- a/plcopen/structures.py	Mon Nov 07 10:55:17 2011 +0100
+++ b/plcopen/structures.py	Tue Nov 08 21:59:22 2011 +0100
@@ -602,8 +602,9 @@
 
 
 # Keywords for Pou Declaration
-POU_KEYWORDS = ["FUNCTION", "END_FUNCTION", "FUNCTION_BLOCK", "END_FUNCTION_BLOCK",
- "PROGRAM", "END_PROGRAM", "EN", "ENO", "F_EDGE", "R_EDGE"]
+POU_BLOCK_START_KEYWORDS = ["FUNCTION", "FUNCTION_BLOCK", "PROGRAM"]
+POU_BLOCK_END_KEYWORDS = ["END_FUNCTION", "END_FUNCTION_BLOCK", "END_PROGRAM"]
+POU_KEYWORDS = ["EN", "ENO", "F_EDGE", "R_EDGE"] + POU_BLOCK_START_KEYWORDS + POU_BLOCK_END_KEYWORDS
 for category in BlockTypes:
     for block in category["list"]:
         if block["name"] not in POU_KEYWORDS:
@@ -611,25 +612,27 @@
 
 
 # Keywords for Type Declaration
-TYPE_KEYWORDS = ["TYPE", "END_TYPE", "STRUCT", "END_STRUCT", "ARRAY", "OF", "T",
- "D", "TIME_OF_DAY", "DATE_AND_TIME"]
+TYPE_BLOCK_START_KEYWORDS = ["TYPE", "STRUCT"]
+TYPE_BLOCK_END_KEYWORDS = ["END_TYPE", "END_STRUCT"]
+TYPE_KEYWORDS = ["ARRAY", "OF", "T", "D", "TIME_OF_DAY", "DATE_AND_TIME"] + TYPE_BLOCK_START_KEYWORDS + TYPE_BLOCK_END_KEYWORDS
 TYPE_KEYWORDS.extend([keyword for keyword in TypeHierarchy.keys() if keyword not in TYPE_KEYWORDS])
 
 
 # Keywords for Variable Declaration
-VAR_KEYWORDS = ["VAR", "VAR_INPUT", "VAR_OUTPUT", "VAR_IN_OUT", "VAR_TEMP", 
- "VAR_EXTERNAL", "END_VAR", "AT", "CONSTANT", "RETAIN", "NON_RETAIN"]
+VAR_BLOCK_START_KEYWORDS = ["VAR", "VAR_INPUT", "VAR_OUTPUT", "VAR_IN_OUT", "VAR_TEMP", "VAR_EXTERNAL"]
+VAR_BLOCK_END_KEYWORDS = ["END_VAR"]
+VAR_KEYWORDS = ["AT", "CONSTANT", "RETAIN", "NON_RETAIN"] + VAR_BLOCK_START_KEYWORDS + VAR_BLOCK_END_KEYWORDS
 
 
 # Keywords for Configuration Declaration
-CONFIG_KEYWORDS = ["CONFIGURATION", "END_CONFIGURATION", "RESOURCE", "ON", "END_RESOURCE",
- "PROGRAM", "WITH", "READ_ONLY", "READ_WRITE", "TASK", "VAR_ACCESS", "VAR_CONFIG", 
- "VAR_GLOBAL", "END_VAR"]
-
+CONFIG_BLOCK_START_KEYWORDS = ["CONFIGURATION", "RESOURCE", "VAR_ACCESS", "VAR_CONFIG", "VAR_GLOBAL"]
+CONFIG_BLOCK_END_KEYWORDS = ["END_CONFIGURATION", "END_RESOURCE", "END_VAR"]
+CONFIG_KEYWORDS = ["ON", "PROGRAM", "WITH", "READ_ONLY", "READ_WRITE", "TASK"] + CONFIG_BLOCK_START_KEYWORDS + CONFIG_BLOCK_END_KEYWORDS
 
 # Keywords for Structured Function Chart
-SFC_KEYWORDS = ["ACTION", "END_ACTION", "INITIAL_STEP", "STEP", "END_STEP", "TRANSITION",
- "FROM", "TO", "END_TRANSITION"]
+SFC_BLOCK_START_KEYWORDS = ["ACTION", "INITIAL_STEP", "STEP", "TRANSITION"]
+SFC_BLOCK_END_KEYWORDS = ["END_ACTION", "END_STEP", "END_TRANSITION"]
+SFC_KEYWORDS = ["FROM", "TO"] + SFC_BLOCK_START_KEYWORDS + SFC_BLOCK_START_KEYWORDS
 
 
 # Keywords for Instruction List
@@ -645,12 +648,17 @@
  "RETURN", "NOT", "MOD", "AND", "XOR", "OR"] + ST_BLOCK_START_KEYWORDS + ST_BLOCK_END_KEYWORDS
 
 # All the keywords of IEC
+IEC_BLOCK_START_KEYWORDS = []
+IEC_BLOCK_END_KEYWORDS = []
 IEC_KEYWORDS = ["E", "TRUE", "FALSE"]
-IEC_KEYWORDS.extend([keyword for keyword in POU_KEYWORDS if keyword not in IEC_KEYWORDS])
-IEC_KEYWORDS.extend([keyword for keyword in TYPE_KEYWORDS if keyword not in IEC_KEYWORDS])
-IEC_KEYWORDS.extend([keyword for keyword in VAR_KEYWORDS if keyword not in IEC_KEYWORDS])
-IEC_KEYWORDS.extend([keyword for keyword in CONFIG_KEYWORDS if keyword not in IEC_KEYWORDS])
-IEC_KEYWORDS.extend([keyword for keyword in SFC_KEYWORDS if keyword not in IEC_KEYWORDS])
-IEC_KEYWORDS.extend([keyword for keyword in IL_KEYWORDS if keyword not in IEC_KEYWORDS])
-IEC_KEYWORDS.extend([keyword for keyword in ST_KEYWORDS if keyword not in IEC_KEYWORDS])
-
+for all_keywords, keywords_list in [(IEC_BLOCK_START_KEYWORDS, [POU_BLOCK_START_KEYWORDS, TYPE_BLOCK_START_KEYWORDS,
+                                                                VAR_BLOCK_START_KEYWORDS, CONFIG_BLOCK_START_KEYWORDS,
+                                                                SFC_BLOCK_START_KEYWORDS, ST_BLOCK_START_KEYWORDS]),
+                                    (IEC_BLOCK_END_KEYWORDS, [POU_BLOCK_END_KEYWORDS, TYPE_BLOCK_END_KEYWORDS,
+                                                              VAR_BLOCK_END_KEYWORDS, CONFIG_BLOCK_END_KEYWORDS,
+                                                              SFC_BLOCK_END_KEYWORDS, ST_BLOCK_END_KEYWORDS]),
+                                    (IEC_KEYWORDS, [POU_KEYWORDS, TYPE_KEYWORDS, VAR_KEYWORDS, CONFIG_KEYWORDS,
+                                                    SFC_KEYWORDS, IL_KEYWORDS, ST_KEYWORDS])]:
+    for keywords in keywords_list:
+        all_keywords.extend([keyword for keyword in keywords if keyword not in all_keywords])
+