use B::Deparse module get source code of subroutine from its reference

code-ref-to-source.pl

# --- use B::Deparse module --- #

use B::Deparse; # or -MO=Deparse

sub mysub {
  my $x  = 20;
  print "The X is : ", $x, "\n";
}

my $deparse = B::Deparse->new;

my $source = $deparse->coderef2text(\&mysub);

print "The source code of mysub is : \n", $source, "\n";

__END__

# ------------------ result ----------------------- #
=begin result
The source code of mysub is : 
{
    use feature 'current_sub', 'evalbytes', 'fc', 'say', 'state', 'switch', 'unicode_strings', 'unicode_eval';
    my $x = 20;
    print 'The X is : ', $x, "\n";
}
=end result
=cut