use Text::CSV_XS;

my $csv = Text::CSV_XS->new();

open(my $IN, '<', 'test.csv'); # ok
open(IN, '<', 'test.csv');     # nope

my $row = $csv->getline(<DATA>); # nope - Usage: Text::CSV_XS::getline(self, io) at test_02.pl line 11, <IN> line 2.
my $row = $csv->getline(<IN>);   # nope - Usage: Text::CSV_XS::getline(self, io) at test_02.pl line 11, <IN> line 2.
my $row = $csv->getline($IN);    # ok

print ${$row}[0];

__DATA__
a,b,c
d,e,f

##</code><code>##

map{$a=1-$_/10;map{$d=$a;$e=$b=$_/20-2;map{($d,$e)=(2*$d*$e+$a,$e**2
-$d**2+$b);$c=$d**2+$e**2>4?$d=8:_}1..50;print$c}0..59;print$/}0..20