For the truly motivated, B::Deparse can serialize into a legible format.

use strict;
use B::Deparse;
my $deparse = B::Deparse->new();
my $func = sub {
    my %hash = @_;
    return $hash{a};
};


my $body = $deparse->coderef2text($func);
print $body;
[download]

You could condition the tree by crawling it and clobbering anything with reftype CODE with sprintf 'sub %s', $deparse->coderef2text($hash{key}). But this still kills closures, and plus is a terrible, terrible idea.