optional parameters in functions

[eluser]richzilla[/eluser]
I dont know if this is a general PHP question or wether code igniter implements its own solution,but here goes. My pages have a builder function for the page that takes 2 parameters, the page to be loaded, and and any data that may or may not be needed by the page. Ive done quite a lot of asp.net/C# and i know you can specify a parameter as optional with the ? symbol, but is there a similar solution in php?

cheers