Wildcard for Strings in E4X?

I'm trying to solve an Actionscript problem usin开发者_开发技巧g E4X. I have an XML like this one:

<root>
  <person firstname="john" lastname="doe" age="21" />
  <person firstname="jayne" lastname="doe" age="35" />
  <person firstname="john" lastname="miller" age="42" />
</root>

I want to have just one function search() that takes three parameters (firstname, lastname, age) and return an XMLList. So the result could look like this:

var result:XMLList = xml..person.(@firstname == firstName && @lastname == lastName && @age == age );

But I don't want to use all three parameters all the time. I would like to have a function that uses a 'wilcard' if the parameter is NULL. So if the wildcard would be "*" the function could look like:

searchPerson( firstName:String ="*", lastName:String = "*" , age:String = "*") {...}

so that I would only pass 'John' for the firstName I'd get the first and the third node in return.

How to do so?

---

The boolean value of attribute("your-attribute") will indicate if a particular attribute is present.

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Ok. I could check all attributes. But I would be left with 7 different options:

• firstName
• secondName
• age
• firstName && secondName
• firstName && age
• lastName && age
• firstName && secondName && age

I'd prefer a one-liner, that's why I'm looking for something like a wildcard.