InfoPath Formula in Rules

I'm new to writing formulas in infopath and can't see what I'm doing wrong with the following:

if (contains(userName(), "\"))
{
substring-after(userName(), "\")
}
else
}
 userName()
}

The above is erroring on the first brace

I can write 2 rules to achieve the same thing but would like to use the above approach if it can be done!?

This a form load rule in infoPath 2010

Solution

Found this which seems to explain it, in case anyone else has the same issue...