=head1 NAME
-namespace::clean - Keep imports out of your namespace
+namespace::clean - Keep imports and functions out of your namespace
=cut
use warnings;
use strict;
-use vars qw( $VERSION );
+use vars qw( $VERSION $STORAGE_VAR );
use Symbol qw( qualify_to_ref );
use Filter::EOF;
=head1 VERSION
-0.01
+0.03
=cut
-$VERSION = 0.01;
+$VERSION = 0.03;
+$STORAGE_VAR = '__NAMESPACE_CLEAN_STORAGE';
=head1 SYNOPSIS
use warnings;
use strict;
- use Carp qw(croak); # will be removed
+ use Carp qw(croak); # 'croak' will be removed
- sub bar { 23 } # will be removed
+ sub bar { 23 } # 'bar' will be removed
+ # remove all previously defined functions
use namespace::clean;
- sub baz { bar() } # still defined, 'bar' still bound
+ sub baz { bar() } # 'baz' still defined, 'bar' still bound
- ### Will print:
- # No
- # No
- # Yes
+ # begin to collection function names from here again
+ no namespace::clean;
+
+ sub quux { baz() } # 'quux' will be removed
+
+ # remove all functions defined after the 'no' unimport
+ use namespace::clean;
+
+ # Will print: 'No', 'No', 'Yes' and 'No'
print +(__PACKAGE__->can('croak') ? 'Yes' : 'No'), "\n";
print +(__PACKAGE__->can('bar') ? 'Yes' : 'No'), "\n";
print +(__PACKAGE__->can('baz') ? 'Yes' : 'No'), "\n";
+ print +(__PACKAGE__->can('quux') ? 'Yes' : 'No'), "\n";
1;
When you define a function, or import one, into a Perl package, it will
naturally also be available as a method. This does not per se cause
problems, but it can complicate subclassing and, for example, plugin
-classes that are included by loading them as base classes.
+classes that are included via multiple inheritance by loading them as
+base classes.
The C<namespace::clean> pragma will remove all previously declared or
imported symbols at the end of the current package's compile cycle.
-This means that functions are already bound by their name, and calls to
-them still work. But they will not be available as methods on your class
-or instances.
+Functions called in the package itself will still be bound by their
+name, but they won't show up as methods on your class or instances.
+
+By unimporting via C<no> you can tell C<namespace::clean> to start
+collecting functions for the next C<use namespace::clean;> specification.
=head1 METHODS
You shouldn't need to call any of these. Just C<use> the package at the
appropriate place.
+=cut
+
=head2 import
Makes a snapshot of the current defined functions and registers a
-L<Filter::EOF> cleanup routine to remove those symbols from the package
-at the end of the compile-time.
+L<Filter::EOF> cleanup routine to remove those symbols at the end
+of the compile-time.
=cut
sub import {
my ($pragma) = @_;
+ # calling class, all current functions and our storage
my $cleanee = caller;
my $functions = $pragma->get_functions($cleanee);
+ my $store = $pragma->get_class_store($cleanee);
- Filter::EOF->on_eof_call(sub {
- for my $f (keys %$functions) {
- next unless $functions->{ $f }
- and *{ $functions->{ $f } }{CODE};
- { no strict 'refs';
+ # register symbols for removal, if they have a CODE entry
+ for my $f (keys %$functions) {
+ next unless $functions->{ $f }
+ and *{ $functions->{ $f } }{CODE};
+ $store->{remove}{ $f } = 1;
+ }
+
+ # register EOF handler on first call to import
+ unless ($store->{handler_is_installed}) {
+ Filter::EOF->on_eof_call(sub {
+ for my $f (keys %{ $store->{remove} }) {
+ next if $store->{exclude}{ $f };
+ no strict 'refs';
delete ${ "${cleanee}::" }{ $f };
}
- }
- });
+ });
+ $store->{handler_is_installed} = 1;
+ }
+
+ return 1;
+}
+
+=head2 unimport
+
+This method will be called when you do a
+
+ no namespace::clean;
+
+It will start a new section of code that defines functions to clean up.
+
+=cut
+
+sub unimport {
+ my ($pragma) = @_;
+
+ # the calling class, the current functions and our storage
+ my $cleanee = caller;
+ my $functions = $pragma->get_functions($cleanee);
+ my $store = $pragma->get_class_store($cleanee);
+
+ # register all unknown previous functions as excluded
+ for my $f (keys %$functions) {
+ next if $store->{remove}{ $f }
+ or $store->{exclude}{ $f };
+ $store->{exclude}{ $f } = 1;
+ }
+
+ return 1;
+}
+
+=head2 get_class_store
+
+This returns a reference to a hash in a passed package containing
+information about function names included and excluded from removal.
+
+=cut
+
+sub get_class_store {
+ my ($pragma, $class) = @_;
+ no strict 'refs';
+ return \%{ "${class}::${STORAGE_VAR}" };
}
=head2 get_functions
my ($pragma, $class) = @_;
return {
- map { @$_ }
- grep { *{ $_->[1] }{CODE} }
- map { [$_, qualify_to_ref( $_, $class )] }
- grep { $_ !~ /::$/ }
- do { no strict 'refs'; keys %{ "${class}::" } }
+ map { @$_ } # key => value
+ grep { *{ $_->[1] }{CODE} } # only functions
+ map { [$_, qualify_to_ref( $_, $class )] } # get globref
+ grep { $_ !~ /::$/ } # no packages
+ do { no strict 'refs'; keys %{ "${class}::" } } # symbol entries
};
}
+=head1 IMPLEMENTATION DETAILS
+
+This module works through the effect that a
+
+ delete $SomePackage::{foo};
+
+will remove the C<foo> symbol from C<$SomePackage> for run time lookups
+(e.g., method calls) but will leave the entry alive to be called by
+already resolved names in the package itself.
+
+A test file has been added to the perl core to ensure that this behaviour
+will be stable in future releases.
+
+Just for completeness sake, if you want to remove the symbol completely,
+use C<undef> instead.
+
=head1 SEE ALSO
L<Filter::EOF>