Calc summation score with BED

#!/usr/bin/perl
use strict;
use warnings;
no warnings 'experimental::smartmatch';
use feature 'say';
sub generate_function {
  my $file = shift;
  my $bed = [];
  open my $f, "< $file" or die;
  while (<$f>) {
    push @$bed, [map { $_ + 0 } (split)[1, 2, 4]];
  }
  close $f;
  return sub {
    my $v = shift;
    my $total = 0;
    for my $i (@$bed) {
      my ($start, $stop, $score) = @$i;
      my $exp = [$start..$stop];
      my $exp2 = [$v..($v+6)];
      if ($v ~~ $exp and ($v + 6) ~~ $exp) {
        $total = 6 * $score;
        last;
      } elsif ($v ~~ $exp) {
        $total = ($stop - $v) * $score;
        next;
      } elsif (($v + 6) ~~ $exp) {
        $total += ($v + 6 - $start) * $score;
        last;
      } elsif ($start ~~ $exp2 and $stop ~~ $exp2) {
        $total += ($stop - $start) * $score;
      }
    }
    return $total;
  };
}
my $f1 = shift || 'test.bedgraph';
my $f2 = shift || 'test.bed';
my $total_score = generate_function $f1;
open my $f, "< $f2" or die;
while (<$f>) {
  my $v = (split)[1] + 0;
  say $total_score->($v);
}
close $f;