@@ -124,11 +124,11 @@
     for lToken in genTokenLines(sTokenLine, dDef):
         # Calculate positions
         dPos = {}   # key: iGroup, value: iToken
         iGroup = 0
         #if iLine == 3971: # debug
-        #    print(lToken.join(" "))
+        #    print(" ".join(lToken))
         for i, sToken in enumerate(lToken):
             if sToken.startswith("(") and sToken.endswith(")"):
                 lToken[i] = sToken[1:-1]
                 iGroup += 1
                 dPos[iGroup] = i + 1    # we add 1, for we count tokens from 1 to n (not from 0)
@@ -313,10 +313,11 @@
     sActions = ""
     nPriority = -1
     dAllGraph = {}
     sGraphName = ""
     iActionBlock = 0
+    aRuleName = set()
 
     for i, sLine in lRule:
         sLine = sLine.rstrip()
         if "\t" in sLine:
             # tabulation not allowed
@@ -326,11 +327,11 @@
             # rules graph call
             m = re.match(r"@@@@GRAPH: *(\w+)", sLine.strip())
             if m:
                 sGraphName = m.group(1)
                 if sGraphName in dAllGraph:
-                    print("Error. Graph name " + sGraphName + " already exists.")
+                    print("Error at line " + i + ". Graph name <" + sGraphName + "> already exists.")
                     exit()
                 dAllGraph[sGraphName] = []
             else:
                 print("Error. Graph name not found at line", i)
                 exit()
@@ -337,10 +338,13 @@
         elif sLine.startswith("__") and sLine.endswith("__"):
             # new rule group
             m = re.match("__(\\w+)(!\\d|)__", sLine)
             if m:
                 sRuleName = m.group(1)
+                if sRuleName in aRuleName:
+                    print("Error at line " + i + ". Rule name <" + sRuleName + "> already exists.")
+                    exit()
                 iActionBlock = 1
                 nPriority = int(m.group(2)[1:]) if m.group(2)  else -1
             else:
                 print("Syntax error in rule group: ", sLine, " -- line:", i)
                 exit()