Infinity recognized as number

[fglock]

perldelta (5.6.1) says:

    Infinity is now recognized as a number.

I'd like to find out what it means, since it doesn't seem to work in Perl expressions like:

 print 1 + Infinity;   # prints "1"

I also tried "Inf", "inf", "infinity", but nothing seems to work.

[Nitrox]

Perl handles infinity as IEEE 754 standards, read more here.

-Nitrox

[crenz]

The point is that now you can compare numbers even if a calculation yields infinity: (try $exponent = 10000)

if (2 ** $exponent > $threshold) {
   do_sth();
}

without getting a "non-numeric value" error. See http://bumppo.net/lists/fun-with-perl/2001/06/msg00031.html

[fglock]

Thanks all. The point is, Perl prints out the Infinity number as "Inf" (FreeBSD) or "inf" (linux). What I learned is that the string "Inf" is just a string.

Now I'm using $inf=10**10**10

[Anonymous Monk]

FWIW, perl 5.16.1 :)

$ perl -e " print 1 + Infinity "
1.#INF
$ perl -e " print 1 + inf"
1.#INF
$ perl -e " print  int inf"
1.#INF
$

[Mr. Muskrat]

I don't know where all it comes into play but try this:


#!/usr/bin/perl
my $int = 999999999999999999999999999999999999;
print $int**$int,$/;


It outputs: 1.#Inf

[shemp]

Nothing to do with infinify, rather a comment on perls numeric interpretation of scalars.
using the addition operator "+", perl will use its numeric interpretation of both operands.
1 evaluates to 1 (like you'd expect)
"Infinity" evaluates to 0 ("zero")
so the addition results in 1

in general, when perl needs a numeric interpretation of a scalar, the value is the value of the maximal length numeric substring that starts at the first character of the scalar.