adventofcode/2017/18/1.pl

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Perl
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2017-12-18 16:39:40 +00:00
use 5.20.0;
my @commands = <>;
my $i = 0;
my %reg;
my $last_played;
use experimental qw/ signatures /;
sub valof($x) {
my $y = $x =~ /\d/ ? $x : $reg{$x};
die $_ if $y eq 'Inf';
return $y;
}
my $vr = qr/(-?\d+|.)/;
while() {
$_ = $commands[$i++];
warn $_ if /\bb\b/;
if( /snd (.)/ ) {
$last_played = valof($1);
}
elsif( /set (.) $vr/ ) {
$reg{$1} = valof($2);
}
elsif( /add (.) $vr/ ) {
$reg{$1} += valof($2);
}
elsif( /mul (.) $vr/ ) {
$reg{$1} *= valof($2);
}
elsif( /mul (.) $vr/ ) {
$reg{$1} *= valof($2);
}
elsif( /mod (.) $vr/ ) {
$reg{$1} %= valof($2);
}
elsif( /jgz (.) $vr/ ) {
next unless $reg{$1} > 0;
$i += -1 + valof($2);
}
elsif( /rcv (.)/ ) {
next unless $reg{$1};
die $last_played;
}
else { die "wut? $_"; }
}