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argument, the constant string C<JSON> as second argument, and all the
values from the JSON array (the values originally returned by the
C<FREEZE> method) as remaining arguments.

The method must then return the object. While technically you can return
any Perl scalar, you might have to enable the C<allow_nonref> setting to
make that work in all cases, so better return an actual blessed reference.

As an example, let's implement a C<THAW> function that regenerates the
C<My::Object> from the C<FREEZE> example earlier:

   sub My::Object::THAW {
      my ($class, $serialiser, $type, $id) = @_;

      $class->new (type => $type, id => $id)
   }


=head1 ENCODING/CODESET FLAG NOTES

This section is taken from JSON::XS.

The interested reader might have seen a number of flags that signify
encodings or codesets - C<utf8>, C<latin1> and C<ascii>. There seems to be
some confusion on what these do, so here is a short comparison:

C<utf8> controls whether the JSON text created by C<encode> (and expected
by C<decode>) is UTF-8 encoded or not, while C<latin1> and C<ascii> only
control whether C<encode> escapes character values outside their respective
codeset range. Neither of these flags conflict with each other, although
some combinations make less sense than others.

Care has been taken to make all flags symmetrical with respect to
C<encode> and C<decode>, that is, texts encoded with any combination of
these flag values will be correctly decoded when the same flags are used
- in general, if you use different flag settings while encoding vs. when
decoding you likely have a bug somewhere.

Below comes a verbose discussion of these flags. Note that a "codeset" is
simply an abstract set of character-codepoint pairs, while an encoding
takes those codepoint numbers and I<encodes> them, in our case into
octets. Unicode is (among other things) a codeset, UTF-8 is an encoding,
and ISO-8859-1 (= latin 1) and ASCII are both codesets I<and> encodings at
the same time, which can be confusing.

=over 4

=item C<utf8> flag disabled

When C<utf8> is disabled (the default), then C<encode>/C<decode> generate
and expect Unicode strings, that is, characters with high ordinal Unicode
values (> 255) will be encoded as such characters, and likewise such
characters are decoded as-is, no changes to them will be done, except
"(re-)interpreting" them as Unicode codepoints or Unicode characters,
respectively (to Perl, these are the same thing in strings unless you do
funny/weird/dumb stuff).

This is useful when you want to do the encoding yourself (e.g. when you
want to have UTF-16 encoded JSON texts) or when some other layer does
the encoding for you (for example, when printing to a terminal using a
filehandle that transparently encodes to UTF-8 you certainly do NOT want
to UTF-8 encode your data first and have Perl encode it another time).

=item C<utf8> flag enabled

If the C<utf8>-flag is enabled, C<encode>/C<decode> will encode all
characters using the corresponding UTF-8 multi-byte sequence, and will
expect your input strings to be encoded as UTF-8, that is, no "character"
of the input string must have any value > 255, as UTF-8 does not allow
that.

The C<utf8> flag therefore switches between two modes: disabled means you
will get a Unicode string in Perl, enabled means you get an UTF-8 encoded
octet/binary string in Perl.

=item C<latin1> or C<ascii> flags enabled

With C<latin1> (or C<ascii>) enabled, C<encode> will escape characters
with ordinal values > 255 (> 127 with C<ascii>) and encode the remaining
characters as specified by the C<utf8> flag.

If C<utf8> is disabled, then the result is also correctly encoded in those
character sets (as both are proper subsets of Unicode, meaning that a
Unicode string with all character values < 256 is the same thing as a
ISO-8859-1 string, and a Unicode string with all character values < 128 is
the same thing as an ASCII string in Perl).

If C<utf8> is enabled, you still get a correct UTF-8-encoded string,
regardless of these flags, just some more characters will be escaped using
C<\uXXXX> then before.

Note that ISO-8859-1-I<encoded> strings are not compatible with UTF-8
encoding, while ASCII-encoded strings are. That is because the ISO-8859-1
encoding is NOT a subset of UTF-8 (despite the ISO-8859-1 I<codeset> being
a subset of Unicode), while ASCII is.

Surprisingly, C<decode> will ignore these flags and so treat all input
values as governed by the C<utf8> flag. If it is disabled, this allows you
to decode ISO-8859-1- and ASCII-encoded strings, as both strict subsets of
Unicode. If it is enabled, you can correctly decode UTF-8 encoded strings.

So neither C<latin1> nor C<ascii> are incompatible with the C<utf8> flag -
they only govern when the JSON output engine escapes a character or not.

The main use for C<latin1> is to relatively efficiently store binary data
as JSON, at the expense of breaking compatibility with most JSON decoders.

The main use for C<ascii> is to force the output to not contain characters
with values > 127, which means you can interpret the resulting string
as UTF-8, ISO-8859-1, ASCII, KOI8-R or most about any character set and
8-bit-encoding, and still get the same data structure back. This is useful
when your channel for JSON transfer is not 8-bit clean or the encoding
might be mangled in between (e.g. in mail), and works because ASCII is a
proper subset of most 8-bit and multibyte encodings in use in the world.

=back

=head1 BUGS

Please report bugs on a specific behavior of this module to RT or GitHub
issues (preferred):