Re^6: NaNs are true

What happens if you add NaN to zero?

The usual rules apply. NaN+0 equals Nan, so ( 0 + $MPFR_NaN_obj ) returns a Math::MPFR object (courtesy of overloading of '+') that has a value of NaN, which is false.

Cheers,
Rob

Comment on Re^6: NaNs are true Download Code

Replies are listed 'Best First'.
Re^7: NaNs are true by jdporter (Paladin) on Mar 01, 2011 at 03:49 UTC
... has a value of NaN, which is false. Ok, I'm confused. In your OP, you say NaNs are true. Now you're saying they're false. Update: I see, you're talking about your overloaded version, which changes the "sign" of NaN. Ok, I agree that changing that is a Bad Idea in general, because of the violation of expectations. So, I guess you'll be stuck (assuming you ditch your overloaded version) doing an explicit test for NaN... `if ( $obj == NaN or $obj ) # true if true or NaN` [download] in which case, you could wrap it in a new method: `sub isTrue # ! { my $obj = shift; $obj == NaN \|\| $obj }` [download]	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^7: NaNs are true
by jdporter (Paladin) on Mar 01, 2011 at 03:49 UTC

... has a value of NaN, which is false.

Ok, I'm confused. In your OP, you say NaNs are true. Now you're saying they're false.

Update: I see, you're talking about your overloaded version, which changes the "sign" of NaN. Ok, I agree that changing that is a Bad Idea in general, because of the violation of expectations.

So, I guess you'll be stuck (assuming you ditch your overloaded version) doing an explicit test for NaN...

  if ( $obj == NaN or $obj ) # true if true or NaN
[download]

  sub isTrue # !
  {
     my $obj = shift;
     $obj == NaN || $obj
  }
[download]

[reply]
[d/l]
[select]