runtime problem

jonagondos has asked for the wisdom of the Perl Monks concerning the following question:

why doesn't this piece code run correctly at runtime i probably dont understand the small arrow ->? compile error during runtime is Scalar::Util::looks_like_number(sv) at test.pl line 16, <STDIN> line 1.

if ($numeral = Scalar::Util->looks_like_number($user_radius)) { full code

#!/usr/bin/perl

use warnings;
use Scalar::Util;

$radius_times = 2;
$radius_times_2 = 3.141592654;
$radius_times_2 *= $radius_times;

while (1) {
print "enter the radius\n";
$user_radius = <STDIN>;

chomp($user_radius);

if (my $numeral = Scalar::Util->looks_like_number($user_radius)) {

$user_radius *= $radius_times_2;

print "circumference is equal to $user_radius\n";
}


else {
    print "no user input\n";
}

}
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Replies are listed 'Best First'.
Re: runtime problem by toolic (Bishop) on Nov 14, 2012 at 17:27 UTC
Use :: instead of -> `if (my $numeral = Scalar::Util::looks_like_number($user_radius)) {` [download] Scalar::Util does not have an object-oriented interface. Similarly, you can also import the sub: `use Scalar::Util qw(looks_like_number); ... if (my $numeral = looks_like_number($user_radius)) {` [download]	[reply] [d/l] [select]
Re: runtime problem by tobyink (Canon) on Nov 14, 2012 at 18:36 UTC
toolic is correct. This is cool though... `sub FakeOO { eval "require $_[0]"; bless \($_[0]), "FakeOO"; } sub FakeOO::AUTOLOAD { my $pkg = ${+shift}; $pkg->can($FakeOO::AUTOLOAD =~ /::(\w+)$/)->(@_); } my $scalar_util = FakeOO("Scalar::Util"); $scalar_util->looks_like_number(123);` [download] `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply] [d/l]
Re^2: runtime problem by ColonelPanic (Friar) on Nov 15, 2012 at 10:29 UTC
Yes, pretty cool. And it also pretty much sums up why Perl is so loved and hated by so many people. You can do any insane, ill-advised thing you want :) When's the last time you used duct tape on a duct? --Larry Wall	[reply]
Re^2: runtime problem by jonagondos (Novice) on Nov 14, 2012 at 20:00 UTC
thanks guys	[reply]

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