use 5.006;
use Carp;
use warnings;
-$VERSION = '0.75';
+use strict;
+use vars qw($VERSION $AUTOLOAD);
+$VERSION = '0.78_06';
# $DB::single=1;
my %symcache;
return $symcache{$pkg,$ref} if $symcache{$pkg,$ref};
$type ||= ref($ref);
my $found;
+ no strict 'refs';
foreach my $sym ( values %{$pkg."::"} ) {
+ use strict;
+ next unless ref ( \$sym ) eq 'GLOB';
return $symcache{$pkg,$ref} = \$sym
if *{$sym}{$type} && *{$sym}{$type} == $ref;
}
my %raw;
my %phase;
my %sigil = (SCALAR=>'$', ARRAY=>'@', HASH=>'%');
+my $global_phase = 0;
+my %global_phases = (
+ BEGIN => 0,
+ CHECK => 1,
+ INIT => 2,
+ END => 3,
+);
+my @global_phases = qw(BEGIN CHECK INIT END);
sub _usage_AH_ {
croak "Usage: use $_[0] autotie => {AttrName => TieClassName,...}";
while (@_) {
my $cmd = shift;
if ($cmd =~ /^autotie((?:ref)?)$/) {
- my $tiedata = '($was_arrayref ? $data : @$data)';
- $tiedata = ($1 ? '$ref, ' : '') . $tiedata;
+ my $tiedata = ($1 ? '$ref, ' : '') . '@$data';
my $mapping = shift;
_usage_AH_ $class unless ref($mapping) eq 'HASH';
while (my($attr, $tieclass) = each %$mapping) {
my $args = $3||'()';
_usage_AH_ $class unless $attr =~ $qual_id
&& $tieclass =~ $qual_id
- && eval "use base $tieclass; 1";
+ && eval "use base q\0$tieclass\0; 1";
if ($tieclass->isa('Exporter')) {
local $Exporter::ExportLevel = 2;
$tieclass->import(eval $args);
warn "Declaration of $name attribute in package $lastattr{pkg} may clash with future reserved word\n"
if $^W and $name !~ /[A-Z]/;
foreach ( @{$validtype{$lastattr{type}}} ) {
+ no strict 'refs';
*{"$lastattr{pkg}::_ATTR_${_}_${name}"} = $lastattr{ref};
}
%lastattr = ();
}
sub AUTOLOAD {
+ return if $AUTOLOAD =~ /::DESTROY$/;
my ($class) = $AUTOLOAD =~ m/(.*)::/g;
$AUTOLOAD =~ m/_ATTR_(.*?)_(.*)/ or
croak "Can't locate class method '$AUTOLOAD' via package '$class'";
- croak "Attribute handler '$3' doesn't handle $2 attributes";
+ croak "Attribute handler '$2' doesn't handle $1 attributes";
}
-sub DESTROY {}
-
-my $builtin = qr/lvalue|method|locked/;
+my $builtin = qr/lvalue|method|locked|unique|shared/;
sub _gen_handler_AH_() {
return sub {
_resolve_lastattr;
my ($pkg, $ref, @attrs) = @_;
+ my (undef, $filename, $linenum) = caller 2;
foreach (@attrs) {
my ($attr, $data) = /^([a-z_]\w*)(?:[(](.*)[)])?$/is or next;
if ($attr eq 'ATTR') {
+ no strict 'refs';
$data ||= "ANY";
$raw{$ref} = $data =~ s/\s*,?\s*RAWDATA\s*,?\s*//;
$phase{$ref}{BEGIN} = 1
$phase{$ref}{CHECK} = 1
if $data =~ s/\s*,?\s*(CHECK)\s*,?\s*//
|| ! keys %{$phase{$ref}};
+ # Added for cleanup to not pollute next call.
+ (%lastattr = ()),
croak "Can't have two ATTR specifiers on one subroutine"
if keys %lastattr;
croak "Bad attribute type: ATTR($data)"
%lastattr=(pkg=>$pkg,ref=>$ref,type=>$data);
}
else {
- my $handler = $pkg->can($attr);
+ my $type = ref $ref;
+ my $handler = $pkg->can("_ATTR_${type}_${attr}");
next unless $handler;
my $decl = [$pkg, $ref, $attr, $data,
- $raw{$handler}, $phase{$handler}];
- _apply_handler_AH_($decl,'BEGIN');
- push @declarations, $decl;
+ $raw{$handler}, $phase{$handler}, $filename, $linenum];
+ foreach my $gphase (@global_phases) {
+ _apply_handler_AH_($decl,$gphase)
+ if $global_phases{$gphase} <= $global_phase;
+ }
+ if ($global_phase != 0) {
+ # if _gen_handler_AH_ is being called after
+ # CHECK it's for a lexical, so make sure
+ # it didn't want to run anything later
+
+ local $Carp::CarpLevel = 2;
+ carp "Won't be able to apply END handler"
+ if $phase{$handler}{END};
+ }
+ else {
+ push @declarations, $decl
+ }
}
$_ = undef;
}
}
}
-*{"MODIFY_${_}_ATTRIBUTES"} = _gen_handler_AH_ foreach @{$validtype{ANY}};
-push @UNIVERSAL::ISA, 'Attribute::Handlers'
- unless grep /^Attribute::Handlers$/, @UNIVERSAL::ISA;
+{
+ no strict 'refs';
+ *{"Attribute::Handlers::UNIVERSAL::MODIFY_${_}_ATTRIBUTES"} =
+ _gen_handler_AH_ foreach @{$validtype{ANY}};
+}
+push @UNIVERSAL::ISA, 'Attribute::Handlers::UNIVERSAL'
+ unless grep /^Attribute::Handlers::UNIVERSAL$/, @UNIVERSAL::ISA;
sub _apply_handler_AH_ {
my ($declaration, $phase) = @_;
- my ($pkg, $ref, $attr, $data, $raw, $handlerphase) = @$declaration;
+ my ($pkg, $ref, $attr, $data, $raw, $handlerphase, $filename, $linenum) = @$declaration;
return unless $handlerphase->{$phase};
# print STDERR "Handling $attr on $ref in $phase with [$data]\n";
my $type = ref $ref;
$attr,
(@$data>1? $data : $data->[0]),
$phase,
+ $filename,
+ $linenum,
);
return 1;
}
-CHECK {
- _resolve_lastattr;
- _apply_handler_AH_($_,'CHECK') foreach @declarations;
-}
+{
+ no warnings 'void';
+ CHECK {
+ $global_phase++;
+ _resolve_lastattr;
+ _apply_handler_AH_($_,'CHECK') foreach @declarations;
+ }
-INIT { _apply_handler_AH_($_,'INIT') foreach @declarations }
+ INIT {
+ $global_phase++;
+ _apply_handler_AH_($_,'INIT') foreach @declarations
+ }
+}
-END { _apply_handler_AH_($_,'END') foreach @declarations }
+END { $global_phase++; _apply_handler_AH_($_,'END') foreach @declarations }
1;
__END__
=head1 VERSION
-This document describes version 0.75 of Attribute::Handlers,
-released September 3, 2001.
+This document describes version 0.78 of Attribute::Handlers,
+released October 5, 2002.
=head1 SYNOPSIS
derived from that package may be given attributes with the same names as
the attribute handler subroutines, which will then be called in one of
the compilation phases (i.e. in a C<BEGIN>, C<CHECK>, C<INIT>, or C<END>
-block).
+block). (C<UNITCHECK> blocks don't correspond to a global compilation
+phase, so they can't be specified here.)
To create a handler, define it as a subroutine with the same name as
the desired attribute, and declare the subroutine itself with the
attribute C<:ATTR>. For example:
- package LoudDecl;
- use Attribute::Handlers;
-
- sub Loud :ATTR {
- my ($package, $symbol, $referent, $attr, $data, $phase) = @_;
- print STDERR
- ref($referent), " ",
- *{$symbol}{NAME}, " ",
- "($referent) ", "was just declared ",
- "and ascribed the ${attr} attribute ",
- "with data ($data)\n",
- "in phase $phase\n";
- }
+ package LoudDecl;
+ use Attribute::Handlers;
+
+ sub Loud :ATTR {
+ my ($package, $symbol, $referent, $attr, $data, $phase, $filename, $linenum) = @_;
+ print STDERR
+ ref($referent), " ",
+ *{$symbol}{NAME}, " ",
+ "($referent) ", "was just declared ",
+ "and ascribed the ${attr} attribute ",
+ "with data ($data)\n",
+ "in phase $phase\n",
+ "in file $filename at line $linenum\n";
+ }
-This creates an handler for the attribute C<:Loud> in the class LoudDecl.
+This creates a handler for the attribute C<:Loud> in the class LoudDecl.
Thereafter, any subroutine declared with a C<:Loud> attribute in the class
LoudDecl:
=item [5]
-the name of the phase in which the handler is being invoked.
+the name of the phase in which the handler is being invoked;
+
+=item [6]
+
+the filename in which the handler is being invoked;
+
+=item [7]
+
+the line number in this file.
=back
the handler get in the way.
You can turn off that eagerness-to-help by declaring
-an attribute handler with the the keyword C<RAWDATA>. For example:
+an attribute handler with the keyword C<RAWDATA>. For example:
sub Raw : ATTR(RAWDATA) {...}
sub Nekkid : ATTR(SCALAR,RAWDATA) {...}
print $next;
}
-In fact, this pattern is so widely applicable that Attribute::Handlers
+Note that, because the C<Cycle> attribute receives its arguments in the
+C<$data> variable, if the attribute is given a list of arguments, C<$data>
+will consist of a single array reference; otherwise, it will consist of the
+single argument directly. Since Tie::Cycle requires its cycling values to
+be passed as an array reference, this means that we need to wrap
+non-array-reference arguments in an array constructor:
+
+ $data = [ $data ] unless ref $data eq 'ARRAY';
+
+Typically, however, things are the other way around: the tieable class expects
+its arguments as a flattened list, so the attribute looks like:
+
+ sub UNIVERSAL::Cycle : ATTR(SCALAR) {
+ my ($package, $symbol, $referent, $attr, $data, $phase) = @_;
+ my @data = ref $data eq 'ARRAY' ? @$data : $data;
+ tie $$referent, 'Tie::Whatever', @data;
+ }
+
+
+This software pattern is so widely applicable that Attribute::Handlers
provides a way to automate it: specifying C<'autotie'> in the
-C<use Attribute::Handlers> statement. So, the previous example,
+C<use Attribute::Handlers> statement. So, the cycling example,
could also be written:
use Attribute::Handlers autotie => { Cycle => 'Tie::Cycle' };
package main;
- my $next : Cycle('A'..'Z'); # $next is now a tied variable
+ my $next : Cycle(['A'..'Z']); # $next is now a tied variable
while (<>) {
print $next;
+Note that we now have to pass the cycling values as an array reference,
+since the C<autotie> mechanism passes C<tie> a list of arguments as a list
+(as in the Tie::Whatever example), I<not> as an array reference (as in
+the original Tie::Cycle example at the start of this section).
+
The argument after C<'autotie'> is a reference to a hash in which each key is
the name of an attribute to be created, and each value is the class to which
variables ascribed that attribute should be tied.
Autoties are most commonly used in the module to which they actually tie,
and need to export their attributes to any module that calls them. To
-facilitiate this, Attribute::Handlers recognizes a special "pseudo-class" --
+facilitate this, Attribute::Handlers recognizes a special "pseudo-class" --
C<__CALLER__>, which may be specified as the qualifier of an attribute:
package Tie::Me::Kangaroo:Down::Sport;
- use Attribute::Handlers autotie => { __CALLER__::Roo => __PACKAGE__ };
+ use Attribute::Handlers autotie => { '__CALLER__::Roo' => __PACKAGE__ };
This causes Attribute::Handlers to define the C<Roo> attribute in the package
that imports the Tie::Me::Kangaroo:Down::Sport module.
+Note that it is important to quote the __CALLER__::Roo identifier because
+a bug in perl 5.8 will refuse to parse it and cause an unknown error.
+
=head3 Passing the tied object to C<tie>
Occasionally it is important to pass a reference to the object being tied
subroutine ceased to exist between the point it was declared and the point
at which its attribute handler(s) would have been called.
+=item C<Won't be able to apply END handler>
+
+You have defined an END handler for an attribute that is being applied
+to a lexical variable. Since the variable may not be available during END
+this won't happen.
+
=back
=head1 AUTHOR
projects / p5sagit/p5-mst-13.2.git / blobdiff