Fix index increment in Signature validation

Author: rayokota

src/jsonata/signature.py

@@ -308,6 +308,7 @@ def validate(self, args: Any, context: Optional[Any]) -> Optional[Any]:
                             arg = args[arg_index] if arg_index < len(args) else None
                             validated_args.append(arg)
                             arg_index += 1
+                index += 1
             return validated_args
         self.throw_validation_error(args, supplied_sig, self.function_name)
 

tests/signature_test.py

@@ -7,7 +7,7 @@ class TestSignature:
     def test_parameters_are_converted_to_arrays(self):
         expr = jsonata.Jsonata("$greet(1,null,3)")
         expr.register_function("greet", jsonata.Jsonata.JFunction(TestSignature.JFunctionCallable1(), "<a?a?a?a?:s>"))
-        assert expr.evaluate(None) == "[[1], [null], [3], [None]]"
+        assert expr.evaluate(None) == "[[1], None, [3], None]"
 
     class JFunctionCallable1(jsonata.Jsonata.JFunctionCallable):
 
@@ -30,3 +30,13 @@ class JFunctionCallable2(jsonata.Jsonata.JFunctionCallable):
 
         def call(self, input, args):
             return None
+
+    def test_var_arg_many(self):
+        expr = jsonata.Jsonata("$customArgs('test',[1,2,3,4],3)")
+        expr.register_function("customArgs", jsonata.Jsonata.JFunction(TestSignature.JFunctionCallable3(), "<sa<n>n:s>"))
+        assert expr.evaluate(None) == "['test', [1, 2, 3, 4], 3]"
+
+    class JFunctionCallable3(jsonata.Jsonata.JFunctionCallable):
+
+        def call(self, input, args):
+            return str(args)