SYNOPSIS # in function metadata result_postfilter => { re => 'str', # convert regex object to string date => 'epoch', # convert date object to an integer Unix time code => 'str', # convert subroutine to string literal 'CODE' } DESCRIPTION NOTE: The use of this property is now deprecated. Generating filtering code for each function is quite wasteful when there are hundreds or more functions that are wrapped. Instead, see Data::Clean::JSON. This property specifies postfilters for function result. Currently the focus of this property is converting values that are unsafe when exporting to JSON/YAML. Value: a hash containing instruction of how to filter. Known keys: * re (filter regex object) With filter values: str (stringify it). * date (date object, such as DateTime in Perl) With filter values: epoch (convert to Unix epoch time). * code (subroutine) With filter values: str (convert to string literal CODE). More sophisticated filtering rules might be specified in the future. Filtering using generated code can be faster since the code will use for() loop and inline conversion instead of callback for each data item (higher subroutine call overhead). NOTES Another alternative is using the encoder's facility, for example the JSON module can convert blessed object: use JSON 2; my $encoder = JSON->new->convert_blessed; { local *DateTime::TO_JSON = sub { $_[0]->ymd }; print $encoder->encode($doc); } But this currently can't convert coderefs. JSON also can't handle circular references, which neither this wrapper property nor the above way can work around. SEE ALSO Perinci