Re: Regex

[Chas. Owens]

On Nov 13, 2007 12:18 PM, Gunnar Hjalmarsson <[EMAIL PROTECTED]> wrote:
> Chas. Owens wrote:
> > On Nov 13, 2007 10:58 AM, Chas. Owens <[EMAIL PROTECTED]> wrote:
> > snip
> >> I believe you want /\d[a-z]{2}/i.
> > snip
> >
> > Oops, I didn't pay attention to my own warning about \d, I should have said
> >
> > /[0-9][a-z]{2}/i
>
> Are you saying that \d is no longer equivalent to [0-9]? If so, which
> digits does \d match besides [0-9]?
snip

Yep, that is what I am saying.  The \d character class matches any
numeric character, and that includes all of the numeric characters in
Unicode.  The following program outputs

Wide character in print at t.pl line 8.
Mongolian digit three is ᠓
it is a number (using \d)
it is not a number (using [0-9])
it is not a number (using looks_like_number)

I assume the reasoning for this is that regexes are text based, not
datatype based.  That is the string "\x{1811}\x{1812}\x{1813}" is a
number ("123" in Mongolian) in text even if it isn't one Perl can do
math with.  <sarcasm>Frankly, I blame all the foreigners, they should
just learn English and use ASCII</sarcasm>

#!/usr/bin/perl

use warnings;
use strict;
use Scalar::Util qw<looks_like_number>;

my $three = "\x{1813}";
print "Mongolian digit three is $three\n";
if ($three =~ /\d/) {
        print "it is a number (using \\d)\n";
} else {
        print "it is not a number (using \\d)\n";
}
if ($three =~ /[0-9]/) {
        print "it is a number (using [0-9])\n";
} else {
        print "it is not a number (using [0-9])\n";
}
if (looks_like_number($three)) {
        print "it is a number (using looks_like_number)\n";
} else {
        print "it is not a number (using looks_like_number)\n";
}