根据xslt中的条件将字符串分配给变量

I want to assign a value to a variable if a particular attribute returns a particular value. In here I want to assign the value "young" to vaiable "person" if pr:all/[@pr:name=current()/@cx:name]/pr:properties/(@ls:middlename) is "cengie". Is that possible?I want to assign a value to a variable if a par