Question

As the title says, in Perl, how can I save a hash that contains a list of subroutine references? For example, I have the following hash that contains the references to the subroutines which are contained in other libraries:

my %testMap = (
  helloTest        => \&runHello,
  goodbyeTest      => \&runGoodbye,
);

When I try to use Data::Dumper in the following matter:

my($out) = new FileHandle ">$fileName"; 
my $serialized => Data::Dumper->Dump([\%testMap], [$HASH_REFERENCE]); 
print $out $serialized; 
close $out;

I end up with a file that looks like the following:

$testMap = {
             'goodbyeTest' => sub { "DUMMY" },
             'helloTest' => sub { "DUMMY" }
           };

When I would like the output to look like what appears in the original listing, is there a way to do this?

Some experimentation with Data::Dumper and Storable have so far turned up nothing and I suspect that it is due to the actual code for the references not being available to the code that is running.

Answer 1

Storable has been able to serialize coderefs since version 2.05.

use strict;
use warnings;
use Storable;
use Data::Dump 'dump';

{
    no warnings;             # Suppress 'used only once' warning
    $Storable::Deparse = 1;  # Needs to be set to true as per docs
    $Storable::Eval    = 1;       # Same as above
}

sub hello_world { print "Hello world!\n" }

my %hash = (
             helloTest => \&hello_world,
             byeTest   => sub { print "Goodbye!\n" },
           );

store \%hash, 'file';            # Could use freeze/thaw for
my $cloned = retrieve( 'file' ); # in-memory serialization

$cloned->{helloTest}();          # Prints 'Hello world!'