Re: list strawman

[Jeffrey Carter <jrcarter@acm.org>]

Mark Lundquist wrote:
> 
> "Thomas Wolf" <t_wolf@angelfire.com> wrote in message
> news:MPG.16a629ebab6a7b63989682@news.ip-plus.net...
> > Some comments on that Strawman 1.4 interface:
> >
> > 1. Generic formals
> > ------------------
> >
> >    generic
> >       type Element is private;
> >    package Containers.Lists.Unbounded is
> >
> > I'd prefer
> >
> >    generic
> >       type Element is private;
> >       with function "=" (Left, Right : Element) return Boolean is <>;
> >    package Containers.Lists.Unbounded is
> >
> > This allows users who have unconventional ideas of equality to provide
> > their own routine, without requiring "normal" users to specify the
> > equality function explicitly.
> 
> Indeed it's a bug in Ada95 if the generic uses "=" without importing it
> explicitly.  Otherwise, an overridden "=" is not visible to the generic, and
> predefined equality "reemerges".
> 
> Don't know if that's been fixedin Ted's latest, it may have...

I realize I've been away for a while and may not have seen some minor
changes to the functionality, but "=" for Elements is not needed to
implement a list. "=" is not used, so there's no need to specify it in
the generic formal part.

What would be better would be some way to specify that the generic uses
assignment but not "=", but Ada does not provide that.

-- 
Jeff Carter
"Death awaits you all, with nasty, big, pointy teeth!"
Monty Python & the Holy Grail