use v6;

sub gen_combine(@ops) {
	return -> Pair $x, Pair $y {
		$y.key == 0 ?? Nil !!
		@ops.map: {;.key.($x.key,$y.key) =>
			 "($x.value() $_.value() $y.value())"};
	}
}

my $c = gen_combine((&infix:<*> => "*",
					  &infix:</> => "/",
		 			  &infix:<%> => "%",
					  &infix:<+> => "+"));
sub infix:<c> {$c($^a,$^b)};

my @combinations := ({-9=>"(-9)",9=>"9"},{},{},{});
for 0..2 -> $n {
	for 0..$n -> $i {
		for (@combinations[$i] Xc @combinations[$n-$i]) -> $x {
				@combinations[$n+1]{$x.key} = $x.value;
		}
	}
}
sub MAIN(Int $n) {
	for (^($n+1)) Z @combinations[3]{^($n+1)} -> $v,$t {
		say $v ~ ($t[0].defined ?? " = $t[0]"!!"");
	}
}