On Jan 2, 2007, at 10:31 AM, Peter Lynch wrote:

> I would like to know if a function has been called with or without an
> optional argument.
>
> If I have -
>
>  def the_Function (a, b = '')
>  end
>
> and I invoke it like this -
>
>  the_Function('a')
>  the_Function('a', '')
>
> is there any way for me to tell within the_Function which form of
> invocation was used?

Not sure if there's something more graceful, but my first instinct  
would be to define it like

def the_function(*args)
   ...
end

Then the function could contain the defaulting logic in the event of  
only one element in the args array.
-Mat