& udefault()
 
  Syntax: udefault([<obj>/]<attr>,<default case>[,<arg>]...)
 
  This function returns the value of the user-defined function as 
  defined by <attr> (or <obj>/<attr>), as if retrieved via the u() 
  function, with <args>, if the attribute exists and is readable by 
  you.
 
  Otherwise, it evaluates the default case, and returns that. The 
  default case is only evaluated if the attribute does not exist or 
  cannot be read.
 
  Example:
 
  > &TEST me=[center(%0,5,*)]
  > say udefault(Test,-- BOOM --,ACK)
  You say "*ACK*"
  > &TEST me
  > say udefault(me/Test,-- BOOM --,ACK)
  You say "-- BOOM --"
 
	See Also: get(), get_eval(), u(), default(), edefault()