From: Vincent Pit <vince@profvince.com>
Date: Tue, 23 Feb 2010 13:42:19 +0000 (+0100)
Subject: Tune the userdata example
X-Git-Tag: v0.41~3
X-Git-Url: http://git.vpit.fr/?a=commitdiff_plain;h=524bcc5a4d2ada4ea2a9ea1784e0f7d0b6acd0d9;p=perl%2Fmodules%2FVariable-Magic.git

Tune the userdata example
---

diff --git a/lib/Variable/Magic.pm b/lib/Variable/Magic.pm
index 04ed9df..991bca1 100644
--- a/lib/Variable/Magic.pm
+++ b/lib/Variable/Magic.pm
@@ -417,7 +417,8 @@ Value to pass with C<op_info> to get a C<B::OP> object representing the current
 
 =head2 Associate an object to any perl variable
 
-This can be useful for passing user data through limited APIs.
+This technique can be useful for passing user data through limited APIs.
+It is similar to using inside-out objects, but without the drawback of having to implement a complex destructor.
 
     {
      package Magical::UserData;
@@ -430,9 +431,9 @@ This can be useful for passing user data through limited APIs.
       my ($var) = @_;
       my $data = &getdata($var, $wiz);
       unless (defined $data) {
-       &cast($var, $wiz);
-       $data = &getdata($var, $wiz);
-       die "Couldn't cast UserData magic onto the variable" unless defined $data;
+       $data = \(my $slot);
+       &cast($var, $wiz, $slot)
+                        or die "Couldn't cast UserData magic onto the variable";
       }
       $$data;
      }