Re: Older Sibling?

Miles Sabin wrote:
> 
> David Brownell wrote,
> > would you seriously expect DOM to save you the work of
> > writing such a simple subroutine?  If so, why?
> 
> How about: because some implementations might be able to
> provide an O(1) implementation, whereas an external routine
> would be likely to be O(number of siblings) or thereabouts.

The original comment was more along the lines of "can't do
this, why?  aaagh!" as I recall ... not the "it's too slow"
that you seem to be suggesting it was.

It's common that some special purpose task can be sped up by
putting it into infrastructure.  But that in itself is rarely
a compelling motivation for making it a "standard, everyone
must implement this" part of an infrastructure.  If everyone
has to pay for it, everyone _ought_ to benefit more or less
equally from it.

- Dave