TYPEMAP
PerlChandra *   T_CHANDRA

INPUT
T_CHANDRA
    if (SvROK($arg) && sv_derived_from($arg, \"Chandra\")) {
        IV tmp = SvIV((SV*)SvRV($arg));
        $var = INT2PTR($type, tmp);
    }
    else
        Perl_croak(aTHX_ \"$var is not of type Chandra\");

OUTPUT
T_CHANDRA
    sv_setref_pv($arg, \"Chandra\", (void*)$var);
