Re: Re: Re: Unrolling recursion

[broquaint]

For those who don't grok pseudocode here's a perl translation for directory traversal without recursion

my @stack = ".";
while(my $cd = pop @stack) {
    opendir(my $dh, $cd) or die("bad dir - $!");
    foreach (readdir($dh)) {
        next if /^\./;
        print $_.$/;
        push @stack, "$cd/$_" if -d "$cd/$_";
    }
}

and with recursion

&traverse(".");
sub traverse {
    my $dir = shift;
    opendir(my $dh, $dir) or die("bad dir - $!");
    foreach (readdir($dh)) {
        next if /^\./;
        print $_.$/;
        &traverse("$dir/$_") if -d "$dir/$_";
    }
}

That's a pretty neat 'trick' which I guess might be how optimising compilers implement some forms of recursion (or something).
HTH

broquaint