Damian Conway wrote:
> but I still have immense difficulty with the notion that:
>
> $x == NaN
>
> doesn't return true if $x contains NaN.
Anyone with a hardware background should have no difficulty with
this concept. All common HDLs have multi-valued logic systems,
including values like '0', '1' and 'x' (Some systems distinguish
9 different values!).
The language Verilog has 2 equality operators. The most common is
"a == b", which returns false if a and/or b contains 'x'. But it
also provides "a === b"; which will return true if a and b are
identical (thus true if a and b are 'x').
The correct value of "NaN == NaN" should, of course, be "NaN".
This value should exponentially spread through the code:
if ('cat' == 'dog')
{
$foo = 1
}
else
{
$foo = 0
}
assert($foo.isNaN); # true!
However, Perl6 is not a hardware simulator, so I have no expectation
that these semantics will be supported.
Dave.
--
Dave Whipp, Senior Verification Engineer,
Fast-Chip inc., 950 Kifer Rd, Sunnyvale, CA. 94086
tel: 408 523 8071; http://www.fast-chip.com
Opinions my own; statements of fact may be in error.
