(posted this in the FB Perl group, but I know a lot of you aren't on Fb, so...

Been writing perl since '95. Only found out today that this idiom for coercing a string into an int can fail:

my $x = int($str+0);

[download]

It fails when the string begins with nan or inf (case insensitive). So, running this:

my @test = qw(in inf info information INF INFO Na Nan Nanny NAN NANNY 
+nan04);
foreach my $x (@test) {
  my $y = int($x);
  printf "%11s -> %s\n", $x, $y;
}

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outputs:

         in -> 0
        inf -> Inf
       info -> Inf
information -> Inf
        INF -> Inf
       INFO -> Inf
         Na -> 0
        Nan -> NaN
      Nanny -> NaN
        NAN -> NaN
      NANNY -> NaN
      nan04 -> NaN

[download]

It feels like a bug that the regex matches on /^(?:nan|inf).*/s (or \w* - I haven't fully tested it. Rather than matching on /^(?:nan|inf)$/s

Just wondered if this actually is a bug. I've always used Math::BigFloat whenever I need accurate math, so I've never used NaN/Inf in code before.

what do you all think?

In reply to Weird behavior of int() by cLive ;-)

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