=head1 VERSION
-Version 0.09
+Version 0.24
=cut
our $VERSION;
BEGIN {
- $VERSION = '0.09';
+ $VERSION = '0.24';
}
=head1 SYNOPSIS
=head1 DESCRIPTION
-Magic is Perl way of enhancing objects. This mechanism let the user add extra data to any variable and overload syntaxical operations (such as access, assignation or destruction) that can be applied to it. With this module, you can add your own magic to any variable without the pain of the C API.
+Magic is Perl way of enhancing objects. This mechanism let the user add extra data to any variable and hook syntaxical operations (such as access, assignation or destruction) that can be applied to it. With this module, you can add your own magic to any variable without the pain of the C API.
+
+Magic differs from tieing and overloading in several ways :
+
+=over 4
+
+=item *
+
+Magic isn't copied on assignation (as for blessed references) : you attach it to variables, not values.
+
+=item *
+
+It doesn't replace the original semantics : magic callbacks trigger before the original action take place, and can't prevent it to happen.
+
+=item *
+
+It's mostly invisible at the Perl level : magical and non-magical variables cannot be distinguished with C<ref>, C<reftype> or another trick.
+
+=item *
+
+It's notably faster, since perl's way of handling magic is lighter by nature, and there's no need for any method resolution.
+
+=back
The operations that can be overloaded are :
=over 4
-=item C<get>
+=item *
+
+C<get>
This magic is invoked when the variable is evaluated (does not include array/hash subscripts and slices).
-=item C<set>
+=item *
+
+C<set>
This one is triggered each time the value of the variable changes (includes array/hash subscripts and slices).
-=item C<len>
+=item *
+
+C<len>
This magic is a little special : it is called when the 'size' or the 'length' of the variable has to be known by Perl. Typically, it's the magic involved when an array is evaluated in scalar context, but also on array assignation and loops (C<for>, C<map> or C<grep>). The callback has then to return the length as an integer.
-=item C<clear>
+=item *
+
+C<clear>
This magic is invoked when the variable is reset, such as when an array is emptied. Please note that this is different from undefining the variable, even though the magic is called when the clearing is a result of the undefine (e.g. for an array, but actually a bug prevent it to work before perl 5.9.5 - see the L<history|/PERL MAGIC HISTORY>).
-=item C<free>
+=item *
+
+C<free>
This one can be considered as an object destructor. It happens when the variable goes out of scope (with the exception of global scope), but not when it is undefined.
-=item C<copy>
+=item *
+
+C<copy>
This magic only applies to tied arrays and hashes. It fires when you try to access or change their elements. It is available on your perl iff C<MGf_COPY> is true.
-=item C<dup>
+=item *
+
+C<dup>
Invoked when the variable is cloned across threads. Currently not available.
-=item C<local>
+=item *
+
+C<local>
When this magic is set on a variable, all subsequent localizations of the variable will trigger the callback. It is available on your perl iff C<MGf_LOCAL> is true.
=over 4
-=item C<fetch>
+=item *
+
+C<fetch>
This magic happens each time an element is fetched from the hash.
-=item C<store>
+=item *
+
+C<store>
This one is called when an element is stored into the hash.
-=item C<exists>
+=item *
+
+C<exists>
This magic fires when a key is tested for existence in the hash.
-=item C<delete>
+=item *
+
+C<delete>
This last one triggers when a key is deleted in the hash, regardless of whether the key actually exists in it.
The places where magic is invoked have changed a bit through perl history. Here's a little list of the most recent ones.
-=head2 B<5.6.x>
-
=over 4
-=item I<p14416> : 'copy' and 'dup' magic.
+=item *
-=back
+B<5.6.x>
-=head2 B<5.9.3>
+I<p14416> : 'copy' and 'dup' magic.
-=over 4
+=item *
-=item 'len' magic is no longer called when pushing an element into a magic array.
+B<5.9.3>
-=item I<p26569> : 'local' magic.
+I<p25854> : 'len' magic is no longer called when pushing an element into a magic array.
-=back
+I<p26569> : 'local' magic.
-=head2 B<5.9.5>
+=item *
-=over 4
+B<5.9.5>
+
+I<p31064> : Meaningful 'uvar' magic.
+
+I<p31473> : 'clear' magic wasn't invoked when undefining an array. The bug is fixed as of this version.
+
+=item *
-=item I<p31064> : Meaningful 'uvar' magic.
+B<5.10.0>
-=item I<p31473> : 'clear' magic wasn't invoked when undefining an array. The bug is fixed as of this version.
+Since C<PERL_MAGIC_uvar> is uppercased, C<hv_magic_check()> triggers 'copy' magic on hash stores for (non-tied) hashes that also have 'uvar' magic.
+
+=item *
+
+B<5.11.x>
+
+I<p32969> : 'len' magic is no longer invoked when calling C<length> with a magical scalar.
=back
When this constant is true, you can use the C<fetch,store,exists,delete> callbacks on hashes.
+=head2 C<VMG_COMPAT_ARRAY_PUSH_NOLEN>
+
+True for perls that don't call 'len' magic when you push an element in a magical array.
+
+=head2 C<VMG_COMPAT_ARRAY_UNDEF_CLEAR>
+
+True for perls that call 'clear' magic when undefining magical arrays.
+
+=head2 C<VMG_COMPAT_SCALAR_LENGTH_NOLEN>
+
+True for perls that don't call 'len' magic when taking the C<length> of a magical scalar.
+
+=head2 C<VMG_PERL_PATCHLEVEL>
+
+The perl patchlevel this module was built with, or C<0> for non-debugging perls.
+
+=head2 C<VMG_THREADSAFE>
+
+True iff this module could have been built with thread-safety features enabled.
+
=head1 FUNCTIONS
=cut
len => sub { my ($ref, $data, $len) = @_; ... ; return $newlen; },
clear => sub { my ($ref, $data) = @_; ... },
free => sub { my ($ref, $data) = @_, ... },
- copy => sub { my ($ref, $data, $elt) = @_; ... },
+ copy => sub { my ($ref, $data, $key, $elt) = @_; ... },
local => sub { my ($ref, $data) = @_; ... },
fetch => sub { my ($ref, $data, $key) = @_; ... },
store => sub { my ($ref, $data, $key) = @_; ... },
=over 4
-=item C<sig>
+=item *
+
+C<sig>
The numerical signature. If not specified or undefined, a random signature is generated. If the signature matches an already defined magic, then the existant magic object is returned.
-=item C<data>
+=item *
+
+C<data>
A code reference to a private data constructor. It is called each time this magic is cast on a variable, and the scalar returned is used as private data storage for it. C<$_[0]> is a reference to the magic object and C<@_[1 .. @_-1]> are all extra arguments that were passed to L</cast>.
-=item C<get>, C<set>, C<len>, C<clear>, C<free>, C<copy>, C<local>, C<fetch>, C<store>, C<exists> and C<delete>
+=item *
-Code references to corresponding magic callbacks. You don't have to specify all of them : the magic associated with undefined entries simply won't be hooked. In those callbacks, C<$_[0]> is always a reference to the magic object and C<$_[1]> is always the private data (or C<undef> when no private data constructor was supplied). In the special case of C<len> magic and when the variable is an array, C<$_[2]> contains its normal length. C<copy> magic receives the current element (i.e. the value) in C<$_[2]>. C<$_[2]> is also the current key in C<fetch>, C<store>, C<exists> and C<delete> callbacks.
+C<get>, C<set>, C<len>, C<clear>, C<free>, C<copy>, C<local>, C<fetch>, C<store>, C<exists> and C<delete>
+
+Code references to corresponding magic callbacks. You don't have to specify all of them : the magic associated with undefined entries simply won't be hooked. In those callbacks, C<$_[0]> is always a reference to the magic object and C<$_[1]> is always the private data (or C<undef> when no private data constructor was supplied). In the special case of C<len> magic and when the variable is an array, C<$_[2]> contains its normal length. C<$_[2]> is the current key in C<copy>, C<fetch>, C<store>, C<exists> and C<delete> callbacks, although for C<copy> it may just be a copy of the actual key so it's useless to (for example) cast magic on it. C<copy> magic also receives the current element (i.e. the value) in C<$_[3]>.
=back
push @cbs, 'dup' if MGf_DUP;
push @cbs, 'local' if MGf_LOCAL;
push @cbs, qw/fetch store exists delete/ if VMG_UVAR;
- return _wizard(map $opts{$_}, @cbs);
+ my $ret = eval { _wizard(map $opts{$_}, @cbs) };
+ if (my $err = $@) {
+ $err =~ s/\sat\s+.*?\n//;
+ croak $err;
+ }
+ return $ret;
}
=head2 C<gensig>
our @EXPORT = ();
our %EXPORT_TAGS = (
'funcs' => [ qw/wizard gensig getsig cast getdata dispell/ ],
- 'consts' => [ qw/SIG_MIN SIG_MAX SIG_NBR MGf_COPY MGf_DUP MGf_LOCAL VMG_UVAR/ ]
+ 'consts' => [ qw/SIG_MIN SIG_MAX SIG_NBR MGf_COPY MGf_DUP MGf_LOCAL VMG_UVAR/,
+ qw/VMG_COMPAT_ARRAY_PUSH_NOLEN VMG_COMPAT_ARRAY_UNDEF_CLEAR/,
+ qw/VMG_COMPAT_SCALAR_LENGTH_NOLEN/,
+ qw/VMG_PERL_PATCHLEVEL/,
+ qw/VMG_THREADSAFE/ ]
);
our @EXPORT_OK = map { @$_ } values %EXPORT_TAGS;
$EXPORT_TAGS{'all'} = [ @EXPORT_OK ];
Glob tests need L<Symbol> (standard since perl 5.002).
+Threads tests need L<threads> and L<threads::shared>.
+
=head1 SEE ALSO
L<perlguts> and L<perlapi> for internal information about magic.
=head1 AUTHOR
-Vincent Pit, C<< <perl at profvince.com> >>
+Vincent Pit, C<< <perl at profvince.com> >>, L<http://www.profvince.com>.
-You can contact me by mail or on #perl @ FreeNode (Prof_Vince).
+You can contact me by mail or on C<irc.perl.org> (vincent).
=head1 BUGS
-Please report any bugs or feature requests to
-C<bug-variable-magic at rt.cpan.org>, or through the web interface at
-L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Variable-Magic>.
-I will be notified, and then you'll automatically be notified of progress on
-your bug as I make changes.
+Please report any bugs or feature requests to C<bug-variable-magic at rt.cpan.org>, or through the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Variable-Magic>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
=head1 SUPPORT
perldoc Variable::Magic
+Tests code coverage report is available at L<http://www.profvince.com/perl/cover/Variable-Magic>.
+
=head1 COPYRIGHT & LICENSE
Copyright 2007-2008 Vincent Pit, all rights reserved.
projects / perl / modules / Variable-Magic.git / blobdiff