[Xotcl] Send NULL arg to Class constructor

[iifat at mail.ru]

> Object instproc F args {
>   puts "CALL [self] [self calledclass]->[self calledproc] $args"
>   set r [next]
>   puts "EXIT [self] [self calledclass]->[self calledproc] ($r)"
>   return $r
> }

Better, imho

Object instproc F args {
  puts "CALL [self] [self calledclass]->[self calledproc] $args"
  catch next r o
  puts "EXIT [self] [self calledclass]->[self calledproc] ($r)"
  return -options $o $r
}