+All the callbacks are expected to return an integer, which is passed straight to the perl magic API.
+However, only the return value of the C<len> callback currently holds a meaning.
+
+=back
+
+ # A simple scalar tracer
+ my $wiz = wizard get => sub { print STDERR "got ${$_[0]}\n" },
+ set => sub { print STDERR "set to ${$_[0]}\n" },
+ free => sub { print STDERR "${$_[0]} was deleted\n" }
+
+=cut
+
+sub wizard {
+ croak 'Wrong number of arguments for wizard()' if @_ % 2;
+ my %opts = @_;
+ my @keys = qw/sig data op_info get set len clear free/;
+ push @keys, 'copy' if MGf_COPY;
+ push @keys, 'dup' if MGf_DUP;
+ push @keys, 'local' if MGf_LOCAL;
+ push @keys, qw/fetch store exists delete copy_key/ if VMG_UVAR;
+ my $ret = eval { _wizard(map $opts{$_}, @keys) };
+ if (my $err = $@) {
+ $err =~ s/\sat\s+.*?\n//;
+ croak $err;
+ }
+ return $ret;
+}
+
+=head2 C<gensig>
+
+With this tool, you can manually generate random magic signature between SIG_MIN and SIG_MAX inclusive.
+That's the way L</wizard> creates them when no signature is supplied.
+
+ # Generate a signature
+ my $sig = gensig;
+
+=head2 C<getsig>
+
+ getsig $wiz
+
+This accessor returns the magic signature of this wizard.
+
+ # Get $wiz signature
+ my $sig = getsig $wiz;
+
+=head2 C<cast>
+
+ cast [$@%&*]var, [$wiz|$sig], ...
+
+This function associates C<$wiz> magic to the variable supplied, without overwriting any other kind of magic.
+You can also supply the numeric signature C<$sig> instead of C<$wiz>.
+It returns true on success or when C<$wiz> magic is already present, C<0> on error, and C<undef> when no magic corresponds to the given signature (in case C<$sig> was supplied).
+All extra arguments specified after C<$wiz> are passed to the private data constructor.
+If the variable isn't a hash, any C<uvar> callback of the wizard is safely ignored.
+
+ # Casts $wiz onto $x. If $wiz isn't a signature, undef can't be returned.
+ my $x;
+ die 'error' unless cast $x, $wiz;
+
+The C<var> argument can be an array or hash value.
+Magic for those behaves like for any other scalar, except that it is dispelled when the entry is deleted from the container.
+For example, if you want to call C<POSIX::tzset> each time the C<'TZ'> environment variable is changed in C<%ENV>, you can use :
+
+ use POSIX;
+ cast $ENV{TZ}, wizard set => sub { POSIX::tzset(); () };
+
+If you want to overcome the possible deletion of the C<'TZ'> entry, you have no choice but to rely on C<store> uvar magic.
+
+=head2 C<getdata>
+
+ getdata [$@%&*]var, [$wiz|$sig]
+
+This accessor fetches the private data associated with the magic C<$wiz> (or the signature C<$sig>) in the variable.
+C<undef> is returned when no such magic or data is found, or when C<$sig> does not represent a current valid magic object.
+
+ # Get the attached data.
+ my $data = getdata $x, $wiz or die 'no such magic or magic has no data';
+
+=head2 C<dispell>
+
+ dispell [$@%&*]variable, [$wiz|$sig]
+
+The exact opposite of L</cast> : it dissociates C<$wiz> magic from the variable.
+You can also pass the magic signature C<$sig> as the second argument.
+True is returned on success, C<0> on error or when no magic represented by C<$wiz> could be found in the variable, and C<undef> when no magic corresponds to the given signature (in case C<$sig> was supplied).
+
+ # Dispell now. If $wiz isn't a signature, undef can't be returned.
+ die 'no such magic or error' unless dispell $x, $wiz;
+