Execute HQ9+: Difference between revisions

=={{header|Perl}}==

This implementation uses the ''switch'' feature.

<lang perl>

#!/usr/bin/perl

use warnings;

use strict;

use feature qw(say switch);

my @programme = <> or die "No input. Specify a program file or pipe it to the standard input.\n";

for (@programme) {

for my $char (split //) {

given ($char) {

when ('H') { hello() }

when ('Q') { quinne(@programme) }

when ('9') { bottles() }

default { die "Unknown instruction $char.\n" } # Comment this line to ignore other instructions.

}

}

}

sub hello {

print 'Hello World';

}

sub quinne {

print @programme;

}

sub bottles {

for my $n (reverse 0 .. 99) {

my $before = bottle_count($n);

my $after = bottle_count($n - 1);

my $action = bottle_action($n);

say "\u$before of beer on the wall, $before of beer.";

say "$action, $after of beer on the wall.";

say q() if $n;

}

}

sub bottle_count {

my $n = shift;

given ($n) {

when (-1) { return '99 bottles' }

when (0) { return 'no more bottles' }

when (1) { return '1 bottle' }

default { return "$n bottles" }

}

}

sub bottle_action {

my $n = shift;

return 'Take one down and pass it around' if $n > 0;

return 'Go to the store and buy some more';

}

</lang>