use 5.010;
use strict;
use File::Temp ();
use Path::Class ();

my $temp  = Path::Class::Dir->new( File::Temp::tempdir() );
my $file1 = $temp->file('file1.txt');
my $file2 = $temp->file('file2.txt');

# Create files to operate on.
# You already have these files, so you don't need to make them.
print { $file1->openw } <<DATA;
pizza
pickle
omellete
coke
blackforest
croissant
DATA

# (note: following includes tabs - beware if
# copying and pasting from PerlMonks!)
print { $file2->openw } <<DATA;
salt	pizza	1
salt	pickle	1
pepper	omelette	1
pepper	pickle	1
sugar	coke	1
DATA

# OK, now let's start the real work...

# List of all meals
my @meals = $file1->slurp(chomp => 1);

# This will help us generate a list of all ingredients.
my %ingredients;

# Record pairings between ingredients and meals
my %pairings;

# Loop through file2 building up previous hashes.
for ($file2->slurp(chomp => 1))
{
	my ($ing, $meal, $bool) = split /\t/;
	
	$ingredients{$ing}     = 1;     # record that the ingredient exists at all
	$pairings{$ing, $meal} = $bool; # record the pairing of ingredient and meal
}

# List of all ingredients
my @ingredients = keys %ingredients;

# For each pair of ingredient and meal...
for my $i (sort @ingredients)
{
	for my $m (sort @meals)
	{
		printf(
			"%s\t%s\t%d\n",  # format string
			$i,  # ingredient
			$m,  # meal
			$pairings{$i, $m},  # paired?
		);
		# Note that $pairings{$i, $m} is
		# converted to an integer by printf
		# because of the '%d' formatting
		# code. Thus if there's no pairing,
		# we get '0'.
	}
}

# Clean up temp dir
$temp->rmtree;

##</code><code>##

my $pairs = iterator_multi(\@ingredients, \@meals);
while (my ($i, $m) = $pairs->())
{
	printf("%s\t%s\t%d\n", $i, $m, !!$pairings{$i, $m});
}

##</code><code>##

say for mapm { join "\t", @_, 0+ $pairings{$_[0], $_[1]} } \@ingredients, \@meals;