AoC 2024, day 4, part 1 (Perl)

#!/usr/bin/perl

use strict;
use warnings;

use feature         qw(say);

use Math::Vector::Real;

my ($vy,$vx) = Math::Vector::Real->canonical_base(2);
my @Dirs = ($vy, $vx, -$vy, -$vx, $vx+$vy, $vx-$vy, -$vx+$vy, -$vx-$vy);

# Read in grid, adding sentinel ~s to right and bottom
my @Grid = map { chomp; [split(//), '~'] } <>;
push( @Grid, [('~') x $Grid[0]->@*] );

sub grid_at ($) { my $p = shift; return ($Grid[$p->[0]][$p->[1]]) }

my @xmas  = split( //, 'XMAS' );
my $part1 = 0;

for (my $y = 0; $y < $#Grid; $y++) {
    SQUARE:
    for (my $x = 0; $x < $#Grid; $x++) {
        my $coord = V($y,$x);
        next SQUARE if (&grid_at($coord) ne 'X');

        DIR:
        for (my $d = 0; $d < @Dirs; $d++) {
            for (my $i = 1; $i < 4; $i++) {
                next DIR  if ($xmas[$i] ne &grid_at($coord + $i * $Dirs[$d]));
            }
            $part1++;
        }
    }
}

say "Part 1: $part1";