[ic] [interchange] Add numeric ordercheck

[Jon Jensen]

On Thu, 25 Mar 2010, Mike Heins wrote:

> I think perhaps I would prefer:
>
> 	use Scalar::Util qw/looks_like_number/;

Well, I was about to commit this, but read the docs for it and saw it 
allows "Inf" and "Infinity" as numbers. That seems unacceptable since it's 
a narrow Perl definition that will fail in SQL, in numbers going to 
payment gateways, etc. It also accepts exponents such as 1e20, which is 
standard floating-point, but not a standard numeric.

It's too bad, because I like the idea of using the fast built-in for this.

I checked out what Regexp::Common offers, and its 'decimal' test allows -. 
and +. through, which seems broken to me.

Both of those allow through 05, 005, etc., which is tolerated by e.g. 
Postgres but in at least Perl and JavaScript may be interpreted as octal. 
I prohibited it in my new routine.

I put together an expanded test that compares the three routines I've been 
looking at. Let me know what you all think, and if there are any other 
test cases we should be considering.

Jon


use strict;
use warnings;
no warnings 'qw';
use Scalar::Util qw/looks_like_number/;
use Regexp::Common;

my @tests = qw/
     1
     0.5
     -1
     -1.0
     -1.0000
     -0.5
     +0.5
     +0.
     +1.
     +.5
     -.5
     -.
     +.
     -2.1.1
     +.1.1
     01
     01.6
     005
     009
     Inf
     Infinity
     Infoobar
     1e20
     1e+20
     1e-20
     1.62e8
     1.
     .1
     1.1.1
     +1
     1,0
/;

my %routines = (
     looks_like_number => sub { looks_like_number($_[0]) },
     custom_regex => sub { defined($_[0]) and $_[0] =~ /\A[-+]?(?:0\.\d*|[1-9]\d*(?:\.\d*)?|(?:[1-9]\d*|)\.\d+)?\z/ },
     'Regexp::Common decimal' => sub { defined($_[0]) and $_[0] =~ /\A$RE{num}{decimal}\z/ },
);

for my $routine (sort keys %routines) {
     print "\n$routine:\n";
     for (@tests) {
         my $result = $routines{$routine}->($_) ? 'true' : 'false';
         printf "\ttesting %-20s: %s\n", "'$_'", $result;
     }
}


-- 
Jon Jensen
End Point Corporation
http://www.endpoint.com/