use v6;

my $fn = $*PROGRAM_NAME;

my $file = open($fn) err die "Can't read file '$fn': $!";
my %braces = ( '('  => ')',
        '{'         => '}',
        '['         => ']',
        );
my @stack;

for =$file -> my $line {
    for ($line.comb(m/<[()\[\]\{\}]>/)) -> my $match {
        if %braces{$match} {
            # öffnende Klammer gefunden
            push @stack, ~$match;
        } else {
            # schliessende Klammer gefunden
            my $expected = %braces{pop @stack};
            if $expected ne $match {
                die "File '$fn' is not balanced: expected '" ~ 
                    $expected ~ "', found '$match'\n";
            }
        }
    }
}


$file.close;

if @stack.elems == 0 {
    say "File $fn is balanced";
} else {
    say "File $fn is not balanced, more opening braces than closing ones";
}