#!/usr/bin/env perl

use strict;
use warnings FATAL => 'all';

use YAML::Any;
use CSV::Writer;
use Getopt::Long;

my @columns;

GetOptions(
    'columns=s@' => sub {
        my ( $opt, $value ) = @_;
        push @columns, split qr{\s*,\s*}, $value;
    }
) and @columns > 0
    or die "Usage: $0 [--columns=...]\n";

my $csv = CSV::Writer->new( columns =>  \@columns );
$csv->write( $csv->columns );

for my $d ( YAML::Any::LoadFile( \*STDIN ) ) {
    $csv->write( $d );
}