> 
> **Possible Duplicate:**  
> 
> [How to Combine Pattern Constraints and Default Values for Function Arguments](https://mathematica.stackexchange.com/questions/4937/how-to-combine-pattern-constraints-and-default-values-for-function-arguments) 
> 
> 
> 

First a simple example: define a function "add" with two arguments, and its second argument should be Positive and have a default value 1.

```
addv1[x_, (y_:1)?Positive] := x + y;
addv2[x_,y?Positive:1] := x + y;

```

these two just don't work as expected.

So is it impossible to use `PatternTest` and `Optional` value on one `Pattern` simultaneously, considering the probability of its default value conflicting with its pattern test?