Re: [sv-bc] Issue 41 - real in associative array

> I took a closer look at issue 41.  The LRM certainly does
> intentionally restrict the existence of "real" in any
> component of an associative array index type.  This is a
> bit odd since the general statement is simply that equality
> (and some internal ordering relation) is defined and certainly
> equality is defined for real.  Personally I think that it makes
> more sense to drop the restriction than to modify the example
> but if there is any concern about dropping the restriction,
> then we should modify the example to be consistent with the
> normative text.

Gord is clearly right to say that equality is defined for 
reals, in the sense that there is an equality comparison
operator and it does something vaguely useful.  However,
I am (as a matter of principle) uncomfortable about
any attempt to use reals to model or represent discrete
values; indeed, I would always regard testing reals for
equality as being fragile and untrustworthy.  You just 
KNOW that someone will complain when this doesn't do 
what they expect:

  real thirty_degrees = $atan(1.0) * 2.0 / 3.0;
  bit visited[real];
  visited[thirty_degrees] = 1;
  assert (visited[$asin(0.5)]);

So I would prefer to see the ballot feedback implemented
as-is by modifying the example to avoid the use of real.
-- 
Jonathan Bromley
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