Note that you can drop the ", 0", the "ref" and both of the "next;"s.

Since you just need pairs, you can even drop the "["s and "]"s, reducing the code to: 

sub genIterator {
    my( $root ) = @_;
    my @stack = ( $root, 0 );
    return sub {
        while( @stack ) {
            my $index = pop @stack;
            my $tree =  pop @stack;
            if( ref( $tree->[$index] ) ) {
                push( @stack, $tree, $index+1, $tree->[$index], 0 );
            } elsif( $index < @$tree ) {
                push( @stack, $tree, $index+1 );
                return $tree->[$index];
            }
         }
         return;     # empty stack
    }
}

[download]

(Not some fundamental change, just a minor reworking.)

- tye        

In reply to Re^2: An iterator for (not "iterating") a recursive data structure. (terser) by tye
in thread An iterator for (not "iterating") a recursive data structure. by BrowserUk

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