The primary thing to realize is that you can't write numbers as 1.234.567,89 in your program, because you can't change Perl's interpretation of your code. However, if you have data in the form of 1.234.567,89, you can -- as the documentation shows -- use it without error.

I could imagine a fairly simple overload module to make all this work, and work transparently. It'd make runtime slower but if its really desired, its certainly possible.

Except that commas and periods are used elsewhere in Perl. You'd have to enforce the user employ specific whitespace:

@array = (1,2,3,4);     # would be a syntax error, no?
@array = (1, 2, 3, 4);  # would be ok
[download]

You'd have to be very careful about the whole thing. I wouldn't even expect Perl 6 to have an easy I18N option about this (but I could be wrong, those Perl 6ers are tough bastards).

---

Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart

use Number::Format::Calc ( -thousands_sep=>"", -decimal_point=>",");
use strict;
use warnings;

while (<DATA>)
{
    my $n = new Number::Format::Calc ($_);
    print $n * 2, "\n";

}
__DATA__
1,1
2,2
3,3
[download]

2,2
4,4
6,6
[download]

This sounds good. I'm going to give it a try.

use strict;
use warnings;

while (<DATA>) {

    s/(\.(\d+))(?=.*,)/$2/g;
    s/(\d+),?(\d*)/print((($1.'.'.$2)*2),"\n")/eg;

}

__DATA__

1,2
1.23,456
1.23.456,789


STDOUT:

2.4
246.912
246913.578
[download]

use strict;
use warnings;

while (<DATA>) {
    chomp;
    s/,/\./;
    $_ *= 2 if $_;
    s/\./,/;
    print "$_\n";
}
__DATA__
1,
2,22

3,345
[download]

EDIT:
japhy: Your link looks promising for providing the simplest solution, but doesn't really explain how. A short piece of code might be nice for us stupid people.

sh1tn: I may be missing something here, but don't numbers usually have only one decimal point?