cbIterator {
    goto STOP if $_ >700;
    print;
} \@nested;
STOP:

##</code><code>##

#! perl -slw
use strict;
use Data::Dump qw[ pp ];

sub genNested {
    my $n = shift;
    map{ rand() < 0.5 ? [ rand(1000), genNested( $n-1 ) ] : rand( 1000 ) } 1 .. $n;
}

sub cbIterator (&$) {
    my( $code, $tree ) = @_;
    for my $i ( 0 .. $#$tree ) {
        if( ref( $tree->[ $i ] ) eq 'ARRAY' ) {
            &cbIterator( $code, $tree->[ $i ] );
        }
        else {
            local $_ = $tree->[ $i ];
            $code->();
        }
    }
}

my @nested = genNested( 3 );
pp \@nested;

my $count=0;
cbIterator {
    goto STOP if $_ >700;
    $count++;
    print;
} \@nested;

STOP:
print "stopped after $count iterations";

__END__
[
  477.675948149653,
  [
    127.346865922796,
    [497.437228434123, 201.338051626486],
    374.088657613129,
  ],
  [
    767.071185158308,
    [597.589516628219, 84.8516920524318],
    [541.772816445729, 983.763599841957],
  ],
]

477.675948149653
127.346865922796
497.437228434123
201.338051626486
374.088657613129
stopped after 5 iterations