X-Git-Url: http://git.vpit.fr/?a=blobdiff_plain;f=lib%2FVariable%2FMagic.pm;h=c600a15ffbbedb89e095710b544822a78626d480;hb=068ea108c28a60581d00b44976dc979860832c8e;hp=954297ea489a64cef8af1fbf72dfe91cde36a583;hpb=1ff75d21f8a370b6533873480725f78eebd70efc;p=perl%2Fmodules%2FVariable-Magic.git
diff --git a/lib/Variable/Magic.pm b/lib/Variable/Magic.pm
index 954297e..c600a15 100644
--- a/lib/Variable/Magic.pm
+++ b/lib/Variable/Magic.pm
@@ -13,13 +13,13 @@ Variable::Magic - Associate user-defined magic to variables from Perl.
=head1 VERSION
-Version 0.36
+Version 0.38
=cut
our $VERSION;
BEGIN {
- $VERSION = '0.36';
+ $VERSION = '0.38';
}
=head1 SYNOPSIS
@@ -208,8 +208,7 @@ BEGIN {
=head2 C
- wizard sig => ...,
- data => sub { ... },
+ wizard data => sub { ... },
get => sub { my ($ref, $data [, $op]) = @_; ... },
set => sub { my ($ref, $data [, $op]) = @_; ... },
len => sub { my ($ref, $data, $len [, $op]) = @_; ... ; return $newlen; },
@@ -231,14 +230,6 @@ It takes a list of keys / values as argument, whose keys can be :
=item *
-C
-
-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
A code reference to a private data constructor.
@@ -303,7 +294,7 @@ Note that C callbacks are I called during global destruction, as th
sub wizard {
croak 'Wrong number of arguments for wizard()' if @_ % 2;
my %opts = @_;
- my @keys = qw/sig data op_info get set len clear free/;
+ my @keys = qw/data op_info get set len clear free/;
push @keys, 'copy' if MGf_COPY;
push @keys, 'dup' if MGf_DUP;
push @keys, 'local' if MGf_LOCAL;
@@ -316,30 +307,12 @@ sub wizard {
return $ret;
}
-=head2 C
-
-With this tool, you can manually generate random magic signature between SIG_MIN and SIG_MAX inclusive.
-That's the way L creates them when no signature is supplied.
-
- # Generate a signature
- my $sig = gensig;
-
-=head2 C
-
- getsig $wiz
-
-This accessor returns the magic signature of this wizard.
-
- # Get $wiz signature
- my $sig = getsig $wiz;
-
=head2 C
- cast [$@%&*]var, [$wiz|$sig], ...
+ cast [$@%&*]var, $wiz, ...
This function associates C<$wiz> magic to the variable supplied, without overwriting any other kind of magic.
-You can also supply the numeric signature C<$sig> instead of C<$wiz>.
-It returns true on success or when C<$wiz> magic is already present, and croaks on error or when no magic corresponds to the given signature (in case a C<$sig> was supplied).
+It returns true on success or when C<$wiz> magic is already present, and croaks on error.
All extra arguments specified after C<$wiz> are passed to the private data constructor in C<@_[1 .. @_-1]>.
If the variable isn't a hash, any C callback of the wizard is safely ignored.
@@ -356,83 +329,28 @@ For example, if you want to call C each time the C<'TZ'> environme
If you want to overcome the possible deletion of the C<'TZ'> entry, you have no choice but to rely on C uvar magic.
-C can be called from any magical callback, and in particular from C.
-This allows you to recursively cast magic on datastructures :
-
- my $wiz;
- $wiz = wizard
- data => sub {
- my ($var, $depth) = @_;
- $depth ||= 0;
- my $r = ref $var;
- if ($r eq 'ARRAY') {
- &cast((ref() ? $_ : \$_), $wiz, $depth + 1) for @$var;
- } elsif ($r eq 'HASH') {
- &cast((ref() ? $_ : \$_), $wiz, $depth + 1) for values %$var;
- }
- return $depth;
- },
- free => sub {
- my ($var, $depth) = @_;
- my $r = ref $var;
- print "free $r at depth $depth\n";
- ();
- };
-
- {
- my %h = (
- a => [ 1, 2 ],
- b => { c => 3 }
- );
- cast %h, $wiz;
- }
-
-When C<%h> goes out of scope, this will print something among the lines of :
-
- free HASH at depth 0
- free HASH at depth 1
- free SCALAR at depth 2
- free ARRAY at depth 1
- free SCALAR at depth 3
- free SCALAR at depth 3
-
-Of course, this example does nothing with the values that are added after the C.
-
=head2 C
- getdata [$@%&*]var, [$wiz|$sig]
+ getdata [$@%&*]var, $wiz
-This accessor fetches the private data associated with the magic C<$wiz> (or the signature C<$sig>) in the variable.
-It croaks when C<$wiz> or C<$sig> do not represent a valid magic object, and returns an empty list if no such magic is attached to the variable or when the wizard has no data constructor.
+This accessor fetches the private data associated with the magic C<$wiz> in the variable.
+It croaks when C<$wiz> do not represent a valid magic object, and returns an empty list if no such magic is attached to the variable or when the wizard has no data constructor.
# Get the attached data, or undef if the wizard does not attach any.
my $data = getdata $x, $wiz;
=head2 C
- dispell [$@%&*]variable, [$wiz|$sig]
+ dispell [$@%&*]variable, $wiz
The exact opposite of L : it dissociates C<$wiz> magic from the variable.
-You can also pass the magic signature C<$sig> as the second argument.
-This function returns true on success, C<0> when no magic represented by C<$wiz> or C<$sig> could be found in the variable, and croaks if the supplied wizard or signature is invalid.
+This function returns true on success, C<0> when no magic represented by C<$wiz> could be found in the variable, and croaks if the supplied wizard is invalid.
# Dispell now.
die 'no such magic in $x' unless dispell $x, $wiz;
=head1 CONSTANTS
-=head2 C
-
-The minimum integer used as a signature for user-defined magic.
-
-=head2 C
-
-The maximum integer used as a signature for user-defined magic.
-
-=head2 C
-
- SIG_NBR = SIG_MAX - SIG_MIN + 1
-
=head2 C
Evaluates to true iff the 'copy' magic is available.
@@ -452,6 +370,11 @@ When this constant is true, you can use the C callbac
=head2 C
True for perls that don't call 'len' magic when you push an element in a magical array.
+Starting from perl 5.11.0, this only refers to pushes in non-void context and hence is false.
+
+=head2 C
+
+True for perls that don't call 'len' magic when you push in void context an element in a magical array.
=head2 C
@@ -486,6 +409,84 @@ Value to pass with C to get the current op name in the magic callbacks.
Value to pass with C to get a C object representing the current op in the magic callbacks.
+=head1 COOKBOOK
+
+=head2 Associate an object to any perl variable
+
+This can be useful for passing user data through limited APIs.
+
+ {
+ package Magical::UserData;
+
+ use Variable::Magic qw/wizard cast getdata/;
+
+ my $wiz = wizard data => sub { \$_[1] };
+
+ sub ud (\[$@%*&]) : lvalue {
+ my ($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;
+ }
+ }
+
+ {
+ BEGIN { *ud = \&Magical::UserData::ud }
+
+ my $cb;
+ $cb = sub { print 'Hello, ', ud(&$cb), "!\n" };
+
+ ud(&$cb) = 'world';
+ $cb->(); # Hello, world!
+ }
+
+=head2 Recursively cast magic on datastructures
+
+C can be called from any magical callback, and in particular from C.
+This allows you to recursively cast magic on datastructures :
+
+ my $wiz;
+ $wiz = wizard data => sub {
+ my ($var, $depth) = @_;
+ $depth ||= 0;
+ my $r = ref $var;
+ if ($r eq 'ARRAY') {
+ &cast((ref() ? $_ : \$_), $wiz, $depth + 1) for @$var;
+ } elsif ($r eq 'HASH') {
+ &cast((ref() ? $_ : \$_), $wiz, $depth + 1) for values %$var;
+ }
+ return $depth;
+ },
+ free => sub {
+ my ($var, $depth) = @_;
+ my $r = ref $var;
+ print "free $r at depth $depth\n";
+ ();
+ };
+
+ {
+ my %h = (
+ a => [ 1, 2 ],
+ b => { c => 3 }
+ );
+ cast %h, $wiz;
+ }
+
+When C<%h> goes out of scope, this will print something among the lines of :
+
+ free HASH at depth 0
+ free HASH at depth 1
+ free SCALAR at depth 2
+ free ARRAY at depth 1
+ free SCALAR at depth 3
+ free SCALAR at depth 3
+
+Of course, this example does nothing with the values that are added after the C.
+
=head1 PERL MAGIC HISTORY
The places where magic is invoked have changed a bit through perl history.
@@ -539,11 +540,13 @@ I : 'len' magic is no longer invoked when calling C with a magic
I : 'len' magic is no longer called when pushing / unshifting an element into a magical array in void context.
The C part was already covered by I.
+I : 'len' magic is called again when pushing into a magical array in non-void context.
+
=back
=head1 EXPORT
-The functions L, L, L, L, L and L are only exported on request.
+The functions L, L, L and L are only exported on request.
All of them are exported by the tags C<':funcs'> and C<':all'>.
All the constants are also only exported on request, either individually or by the tags C<':consts'> and C<':all'>.
@@ -554,10 +557,13 @@ use base qw/Exporter/;
our @EXPORT = ();
our %EXPORT_TAGS = (
- 'funcs' => [ qw/wizard gensig getsig cast getdata dispell/ ],
+ 'funcs' => [ qw/wizard cast getdata dispell/ ],
'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_UNSHIFT_NOLEN_VOID VMG_COMPAT_ARRAY_UNDEF_CLEAR VMG_COMPAT_SCALAR_LENGTH_NOLEN/,
+ qw/MGf_COPY MGf_DUP MGf_LOCAL VMG_UVAR/,
+ qw/VMG_COMPAT_ARRAY_PUSH_NOLEN VMG_COMPAT_ARRAY_PUSH_NOLEN_VOID/,
+ qw/VMG_COMPAT_ARRAY_UNSHIFT_NOLEN_VOID/,
+ qw/VMG_COMPAT_ARRAY_UNDEF_CLEAR/,
+ qw/VMG_COMPAT_SCALAR_LENGTH_NOLEN/,
qw/VMG_PERL_PATCHLEVEL/,
qw/VMG_THREADSAFE VMG_FORKSAFE/,
qw/VMG_OP_INFO_NAME VMG_OP_INFO_OBJECT/