Test 'delete' uvar magic and introduce VMG_COMPAT_HASH_DELETE_NOUVAR_VOID

[perl/modules/Variable-Magic.git] / README

diff --git a/README b/README
index 0f2d45931bb6c5ac0286db032e98c10e1a8daa6b..ac81e42c52bcf6d095d254e9dcbd72d4238ba4e6 100644 (file)
--- a/README
+++ b/README
@@ -2,10 +2,10 @@ NAME
     Variable::Magic - Associate user-defined magic to variables from Perl.
 
 VERSION
-    Version 0.39
+    Version 0.46
 
 SYNOPSIS
-        use Variable::Magic qw/wizard cast VMG_OP_INFO_NAME/;
+        use Variable::Magic qw<wizard cast VMG_OP_INFO_NAME>;
 
         { # A variable tracer
          my $wiz = wizard set  => sub { print "now set to ${$_[0]}!\n" },
@@ -30,8 +30,8 @@ SYNOPSIS
         }
 
 DESCRIPTION
-    Magic is Perl way of enhancing objects. This mechanism lets the user add
-    extra data to any variable and hook syntaxical operations (such as
+    Magic is Perl's way of enhancing variables. This mechanism lets the user
+    add extra data to any variable and hook syntactical operations (such as
     access, assignment or destruction) that can be applied to it. With this
     module, you can add your own magic to any variable without having to
     write a single line of XS.
@@ -52,12 +52,12 @@ DESCRIPTION
 
     *   It doesn't replace the original semantics.
 
-        Magic callbacks usually trigger before the original action take
-        place, and can't prevent it to happen. This also makes catching
-        individual events easier than with "tie", where you have to provide
-        fallbacks methods for all actions by usually inheriting from the
-        correct "Tie::Std*" class and overriding individual methods in your
-        own class.
+        Magic callbacks usually get triggered before the original action
+        takes place, and can't prevent it from happening. This also makes
+        catching individual events easier than with "tie", where you have to
+        provide fallbacks methods for all actions by usually inheriting from
+        the correct "Tie::Std*" class and overriding individual methods in
+        your own class.
 
     *   It's type-agnostic.
 
@@ -307,7 +307,8 @@ CONSTANTS
 
   "VMG_UVAR"
     When this constant is true, you can use the "fetch,store,exists,delete"
-    callbacks on hashes.
+    callbacks on hashes. Initial VMG_UVAR capability was introduced in perl
+    5.9.5, with a fully functional implementation shipped with perl 5.10.0.
 
   "VMG_COMPAT_ARRAY_PUSH_NOLEN"
     True for perls that don't call 'len' magic when you push an element in a
@@ -329,6 +330,9 @@ CONSTANTS
     True for perls that don't call 'len' magic when taking the "length" of a
     magical scalar.
 
+  "VMG_COMPAT_GLOB_GET"
+    True for perls that call 'get' magic for operations on globs.
+
   "VMG_PERL_PATCHLEVEL"
     The perl patchlevel this module was built with, or 0 for non-debugging
     perls.
@@ -352,12 +356,14 @@ CONSTANTS
 
 COOKBOOK
   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;
 
-         use Variable::Magic qw/wizard cast getdata/;
+         use Variable::Magic qw<wizard cast getdata>;
 
          my $wiz = wizard data => sub { \$_[1] };
 
@@ -365,9 +371,9 @@ COOKBOOK
           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;
          }
@@ -490,9 +496,15 @@ CAVEATS
     this destructor won't be called because the wizard will be destroyed
     first.
 
+    In order to define magic on hash members, you need at least perl 5.10.0
+    (see "VMG_UVAR")
+
 DEPENDENCIES
     perl 5.8.
 
+    A C compiler. This module may happen to build with a C++ compiler as
+    well, but don't rely on it, as no guarantee is made in this regard.
+
     Carp (standard since perl 5), XSLoader (standard since perl 5.006).
 
     Copy tests need Tie::Array (standard since perl 5.005) and Tie::Hash
@@ -531,7 +543,7 @@ SUPPORT
     <http://www.profvince.com/perl/cover/Variable-Magic>.
 
 COPYRIGHT & LICENSE
-    Copyright 2007-2009 Vincent Pit, all rights reserved.
+    Copyright 2007,2008,2009,2010,2011 Vincent Pit, all rights reserved.
 
     This program is free software; you can redistribute it and/or modify it
     under the same terms as Perl itself.