diff --git a/src/jsonata/jexception.py b/src/jsonata/jexception.py
index 79d09bf..1c51b95 100644
--- a/src/jsonata/jexception.py
+++ b/src/jsonata/jexception.py
@@ -30,17 +30,19 @@ class JException(RuntimeError):
     location: int
     current: Optional[Any]
     expected: Optional[Any]
+    extra: Optional[Any]
 
     type: Optional[str]
 
     # remaining: Sequence[tokenizer.Tokenizer.Token] | None
 
-    def __init__(self, error, location=0, current_token=None, expected=None):
-        super().__init__(JException.msg(error, location, current_token, expected))
+    def __init__(self, error, location=0, *args: Any):
+        super().__init__(JException.msg(error, location, *args))
         self.error = error
         self.location = location
-        self.current = current_token
-        self.expected = expected
+        self.current = args[0] if len(args) > 0 else None
+        self.expected = args[1] if len(args) > 1 else None
+        self.extra = args[2] if len(args) > 2 else None
 
         self.type = None
         self.remaining = None
@@ -79,7 +81,7 @@ def get_expected(self) -> Optional[Any]:
     # @return
     #     
     def get_detailed_error_message(self) -> str:
-        return JException.msg(self.error, self.location, self.current, self.expected, True)
+        return JException.msg(self.error, self.location, self.current, self.expected, self.extra, details=True)
 
     #
     # Generate error message from given error code
@@ -95,23 +97,23 @@ def get_detailed_error_message(self) -> str:
     # @return
     #     
     @staticmethod
-    def msg(error: str, location: int, arg1: Optional[Any], arg2: Optional[Any], details: bool = False) -> str:
+    def msg(error: str, location: int, *args: Any, details: bool = False) -> str:
         message = JException.error_codes.get(error)
 
         if message is None:
             # unknown error code
             return "JSonataException " + str(error) + (
-                " {code=unknown position=" + str(location) + " arg1=" + arg1 + " arg2=" + arg2 + "}" if details else "")
+                " {code=unknown position=" + str(location) + " arg1=" + str(args[0] if len(args) > 0 else None) + " arg2=" + str(args[1] if len(args) > 1 else None) + "}" if details else "")
 
         formatted = message
 
         if formatted == "{{{message}}}":
-            return str(arg1)
+            return str(args[0]) if args else ""
 
         # Replace any {{var}} with format "{}"
         formatted = re.sub("\\{\\{\\w+\\}\\}", "{}", formatted)
 
-        formatted = formatted.format(arg1, arg2)
+        formatted = formatted.format(*args)
 
         if details:
             formatted = formatted + " {code=" + error
diff --git a/src/jsonata/jsonata.py b/src/jsonata/jsonata.py
index 8248db4..fe01c20 100644
--- a/src/jsonata/jsonata.py
+++ b/src/jsonata/jsonata.py
@@ -857,7 +857,7 @@ def evaluate_comparison_expression(self, lhs: Optional[Any], rhs: Optional[Any],
 
             else:
 
-                raise jexception.JException("T2009", 0, lhs, rhs)
+                raise jexception.JException("T2009", 0, lhs, op, rhs)
 
         if op == "<":
             result = lhs < rhs
diff --git a/src/jsonata/signature.py b/src/jsonata/signature.py
index 8e6d60d..5158a46 100644
--- a/src/jsonata/signature.py
+++ b/src/jsonata/signature.py
@@ -298,7 +298,7 @@ def validate(self, args: Any, context: Optional[Any]) -> Optional[Any]:
                                                         array_ok = False
                                                         break
                                 if not array_ok:
-                                    raise jexception.JException("T0412", -1, arg, param.subtype)
+                                    raise jexception.JException("T0412", -1, arg_index + 1, self.function_name, param.subtype)
                                 # the function expects an array. If it's not one, make it so
                                 if single != "a":
                                     arg = [arg]