Re^3: Converting boolean values in XMLout

[ikegami]

decode_json uses JSON::true or JSON::false for the first instance it comes across, but then adds hash references to an existing true or false for all subsequent instances.

No, not quite.

When JSON::XS is loaded, it creates two objects

$JSON::XS::true  = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };
$JSON::XS::false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };

No other instances are ever created. No references to those are created. Those two objects are used everywhere.

There's probably a neat way to use Rmap to do the walking, but it was beyond my abilities I'm afraid. :(

It's refusing to visit the same reference twice. You could probably mess with its seen method (which appears to be a way at peeking at the module's internals).

[perlyogi]

The exact code for perl to take into consideration multiple routes to the same node so that rmap_ref need not be called multiple times would be

rmap_ref { $_[0]{seen} = {}; $_ = "$_" if JSON::is_bool($_) } $result;