RE: [sv-ec] sub-class constructor

Tom,

> The Doulos statement means that if EtherPacket has a user-defined 
> new(), then it still requires "super.new(5)" (or just "super.new"?)

I think it's clear that, even on the most charitable reading,
that part of our Guide is poorly worded; and in any case it
certainly has no formal authority.  I accept that it needs
rephrasing and I've already said I will set that in motion.

However, the LRM's discussion isn't perfect either; the line

  class EtherPacket extends Packet(5);

appears to be illegal given the earlier examples, none of which
seems to have a Packet class whose constructor can accept 
a single integer argument by position.  This (admittedly minor)
confusion seems to have been preserved in the latest ballot draft.

It seems to me that users will be well advised to err on the
side of conservatism: in particular...
  - avoiding any call to a virtual method of a class
    from its constructor;
  - avoiding any use at all of class members or methods,
    other than statics, in the arguments to super.new().
But it's good to see consensus that it's OK to use expressions
to calculate the values of arguments to super.new().
-- 
Jonathan Bromley
Consultant

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