File | /usr/local/lib/perl5/5.10.1/base.pm |
Statements Executed | 2275 |
Statement Execution Time | 6.39ms |
Calls | P | F | Exclusive Time |
Inclusive Time |
Subroutine |
---|---|---|---|---|---|
79 | 79 | 72 | 13.2ms | 22.8ms | import | base::
88 | 1 | 1 | 512µs | 512µs | has_version | base::
88 | 1 | 1 | 250µs | 250µs | has_fields | base::
88 | 1 | 1 | 197µs | 197µs | has_attr | base::
1 | 1 | 1 | 14µs | 34µs | BEGIN@3 | base::
1 | 1 | 1 | 8µs | 47µs | BEGIN@4 | base::
0 | 0 | 0 | 0s | 0s | __ANON__[:54] | base::
0 | 0 | 0 | 0s | 0s | __ANON__[:61] | base::
0 | 0 | 0 | 0s | 0s | get_attr | base::
0 | 0 | 0 | 0s | 0s | inherit_fields | base::
Line | State ments |
Time on line |
Calls | Time in subs |
Code |
---|---|---|---|---|---|
1 | package base; | ||||
2 | |||||
3 | 3 | 27µs | 2 | 54µs | # spent 34µs (14+20) within base::BEGIN@3 which was called
# once (14µs+20µs) by Class::MOP::Mixin::AttributeCore::BEGIN@12 at line 3 # spent 34µs making 1 call to base::BEGIN@3
# spent 20µs making 1 call to strict::import |
4 | 3 | 811µs | 2 | 86µs | # spent 47µs (8+39) within base::BEGIN@4 which was called
# once (8µs+39µs) by Class::MOP::Mixin::AttributeCore::BEGIN@12 at line 4 # spent 47µs making 1 call to base::BEGIN@4
# spent 39µs making 1 call to vars::import |
5 | 1 | 800ns | $VERSION = '2.14'; | ||
6 | 1 | 24µs | $VERSION = eval $VERSION; | ||
7 | |||||
8 | # constant.pm is slow | ||||
9 | sub SUCCESS () { 1 } | ||||
10 | |||||
11 | sub PUBLIC () { 2**0 } | ||||
12 | sub PRIVATE () { 2**1 } | ||||
13 | sub INHERITED () { 2**2 } | ||||
14 | sub PROTECTED () { 2**3 } | ||||
15 | |||||
16 | |||||
17 | 1 | 800ns | my $Fattr = \%fields::attr; | ||
18 | |||||
19 | # spent 250µs within base::has_fields which was called 88 times, avg 3µs/call:
# 88 times (250µs+0s) by base::import at line 113, avg 3µs/call | ||||
20 | 264 | 328µs | my($base) = shift; | ||
21 | my $fglob = ${"$base\::"}{FIELDS}; | ||||
22 | return( ($fglob && 'GLOB' eq ref($fglob) && *$fglob{HASH}) ? 1 : 0 ); | ||||
23 | } | ||||
24 | |||||
25 | # spent 512µs within base::has_version which was called 88 times, avg 6µs/call:
# 88 times (512µs+0s) by base::import at line 83, avg 6µs/call | ||||
26 | 264 | 568µs | my($base) = shift; | ||
27 | my $vglob = ${$base.'::'}{VERSION}; | ||||
28 | return( ($vglob && *$vglob{SCALAR}) ? 1 : 0 ); | ||||
29 | } | ||||
30 | |||||
31 | # spent 197µs within base::has_attr which was called 88 times, avg 2µs/call:
# 88 times (197µs+0s) by base::import at line 113, avg 2µs/call | ||||
32 | 264 | 233µs | my($proto) = shift; | ||
33 | my($class) = ref $proto || $proto; | ||||
34 | return exists $Fattr->{$class}; | ||||
35 | } | ||||
36 | |||||
37 | sub get_attr { | ||||
38 | $Fattr->{$_[0]} = [1] unless $Fattr->{$_[0]}; | ||||
39 | return $Fattr->{$_[0]}; | ||||
40 | } | ||||
41 | |||||
42 | 1 | 1µs | if ($] < 5.009) { | ||
43 | *get_fields = sub { | ||||
44 | # Shut up a possible typo warning. | ||||
45 | () = \%{$_[0].'::FIELDS'}; | ||||
46 | my $f = \%{$_[0].'::FIELDS'}; | ||||
47 | |||||
48 | # should be centralized in fields? perhaps | ||||
49 | # fields::mk_FIELDS_be_OK. Peh. As long as %{ $package . '::FIELDS' } | ||||
50 | # is used here anyway, it doesn't matter. | ||||
51 | bless $f, 'pseudohash' if (ref($f) ne 'pseudohash'); | ||||
52 | |||||
53 | return $f; | ||||
54 | } | ||||
55 | } | ||||
56 | else { | ||||
57 | *get_fields = sub { | ||||
58 | # Shut up a possible typo warning. | ||||
59 | () = \%{$_[0].'::FIELDS'}; | ||||
60 | return \%{$_[0].'::FIELDS'}; | ||||
61 | } | ||||
62 | 1 | 3µs | } | ||
63 | |||||
64 | # spent 22.8ms (13.2+9.58) within base::import which was called 79 times, avg 288µs/call:
# once (492µs+4.50ms) by Moose::Meta::Attribute::BEGIN@20 at line 20 of Moose/Meta/Attribute.pm
# once (2.03ms+1.71ms) by Sub::Name::BEGIN@50 at line 50 of Sub/Name.pm
# once (1.46ms+1.89ms) by DateTime::Locale::en_US::BEGIN@25 at line 25 of DateTime/Locale/en_US.pm
# once (536µs+1.72ms) by Class::MOP::Class::BEGIN@22 at line 22 of Class/MOP/Class.pm
# once (590µs+1.04ms) by Class::MOP::Method::Accessor::BEGIN@14 at line 14 of Class/MOP/Method/Accessor.pm
# once (473µs+517µs) by DateTime::TimeZone::Floating::BEGIN@9 at line 9 of DateTime/TimeZone/Floating.pm
# once (651µs+202µs) by Class::MOP::Method::Wrapped::BEGIN@14 at line 14 of Class/MOP/Method/Wrapped.pm
# once (569µs+183µs) by Class::MOP::Method::Constructor::BEGIN@14 at line 14 of Class/MOP/Method/Constructor.pm
# once (372µs+109µs) by Moose::Meta::Method::Overridden::BEGIN@10 at line 10 of Moose/Meta/Method/Overridden.pm
# once (317µs+119µs) by Class::MOP::Mixin::AttributeCore::BEGIN@12 at line 12 of Class/MOP/Mixin/AttributeCore.pm
# once (301µs+78µs) by Class::MOP::Instance::BEGIN@13 at line 13 of Class/MOP/Instance.pm
# once (94µs+22µs) by Test::Deep::SuperHash::BEGIN@60 at line 60 of Test/Deep/Hash.pm
# once (74µs+14µs) by Test::Deep::SuperHashKeys::BEGIN@42 at line 42 of Test/Deep/HashKeys.pm
# once (76µs+12µs) by Test::Deep::SuperHashKeysOnly::BEGIN@100 at line 100 of Test/Deep/HashKeysOnly.pm
# once (57µs+24µs) by Moose::Meta::Method::Constructor::BEGIN@12 at line 12 of Moose/Meta/Method/Constructor.pm
# once (65µs+12µs) by Test::Deep::SuperHashElements::BEGIN@70 at line 70 of Test/Deep/HashElements.pm
# once (63µs+10µs) by Moose::Meta::TypeCoercion::Union::BEGIN@14 at line 14 of Moose/Meta/TypeCoercion/Union.pm
# once (47µs+24µs) by Moose::Meta::Method::Accessor::BEGIN@11 at line 11 of Moose/Meta/Method/Accessor.pm
# once (46µs+24µs) by SimpleDB::Client::Exception::BEGIN@3 at line 3 of (eval 0)[Exception/Class.pm:172] at line 172 of Exception/Class.pm
# once (46µs+22µs) by Moose::Meta::Role::BEGIN@23 at line 23 of Moose/Meta/Role.pm
# once (41µs+27µs) by Class::MOP::Attribute::BEGIN@17 at line 17 of Class/MOP/Attribute.pm
# once (43µs+23µs) by Moose::Meta::Method::Destructor::BEGIN@15 at line 15 of Moose/Meta/Method/Destructor.pm
# once (42µs+23µs) by Moose::Meta::Method::Delegation::BEGIN@14 at line 14 of Moose/Meta/Method/Delegation.pm
# once (40µs+20µs) by Exception::Class::Base::BEGIN@11 at line 11 of Exception/Class/Base.pm
# once (39µs+19µs) by MooseX::Types::Util::BEGIN@13 at line 13 of MooseX/Types/Util.pm
# once (37µs+18µs) by JSON::BEGIN@6 at line 6 of JSON.pm
# once (39µs+16µs) by Test::Deep::SubHash::BEGIN@83 at line 83 of Test/Deep/Hash.pm
# once (39µs+14µs) by Moose::Meta::Role::Composite::BEGIN@13 at line 13 of Moose/Meta/Role/Composite.pm
# once (41µs+11µs) by Moose::Meta::Role::Method::BEGIN@11 at line 11 of Moose/Meta/Role/Method.pm
# once (37µs+15µs) by Test::Deep::SubHashKeys::BEGIN@56 at line 56 of Test/Deep/HashKeys.pm
# once (34µs+16µs) by DateTime::Infinite::BEGIN@11 at line 11 of DateTime/Infinite.pm
# once (38µs+11µs) by SimpleDB::Class::Exception::ObjectNotFound::BEGIN@3 at line 3 of (eval 0)[Exception/Class.pm:172] at line 172 of Exception/Class.pm
# once (36µs+13µs) by Class::MOP::Mixin::HasAttributes::BEGIN@13 at line 13 of Class/MOP/Mixin/HasAttributes.pm
# once (34µs+12µs) by Moose::Meta::TypeConstraint::Registry::BEGIN@14 at line 14 of Moose/Meta/TypeConstraint/Registry.pm
# once (35µs+12µs) by Moose::Meta::Role::Application::RoleSummation::BEGIN@15 at line 15 of Moose/Meta/Role/Application/RoleSummation.pm
# once (33µs+13µs) by Moose::Meta::Instance::BEGIN@11 at line 11 of Moose/Meta/Instance.pm
# once (35µs+11µs) by SimpleDB::Client::Exception::Response::BEGIN@3 at line 3 of (eval 0)[Exception/Class.pm:172] at line 172 of Exception/Class.pm
# once (33µs+13µs) by Moose::Meta::Class::BEGIN@25 at line 25 of Moose/Meta/Class.pm
# once (32µs+13µs) by Test::Deep::SubHashKeysOnly::BEGIN@114 at line 114 of Test/Deep/HashKeysOnly.pm
# once (32µs+13µs) by Test::Deep::SubHashElements::BEGIN@83 at line 83 of Test/Deep/HashElements.pm
# once (29µs+16µs) by Moose::Meta::Class::Immutable::Trait::BEGIN@12 at line 12 of Moose/Meta/Class/Immutable/Trait.pm
# once (31µs+12µs) by Moose::Meta::Role::Application::ToClass::BEGIN@14 at line 14 of Moose/Meta/Role/Application/ToClass.pm
# once (32µs+11µs) by Variable::Magic::BEGIN@560 at line 560 of Variable/Magic.pm
# once (30µs+13µs) by Class::MOP::Mixin::HasMethods::BEGIN@14 at line 14 of Class/MOP/Mixin/HasMethods.pm
# once (30µs+12µs) by Moose::Meta::Role::Attribute::BEGIN@13 at line 13 of Moose/Meta/Role/Attribute.pm
# once (31µs+11µs) by Moose::Meta::TypeConstraint::Role::BEGIN@14 at line 14 of Moose/Meta/TypeConstraint/Role.pm
# once (30µs+12µs) by Moose::Meta::Role::Application::ToInstance::BEGIN@13 at line 13 of Moose/Meta/Role/Application/ToInstance.pm
# once (28µs+13µs) by Moose::Meta::Role::Method::Required::BEGIN@11 at line 11 of Moose/Meta/Role/Method/Required.pm
# once (31µs+11µs) by Moose::Meta::Method::Augmented::BEGIN@10 at line 10 of Moose/Meta/Method/Augmented.pm
# once (29µs+12µs) by Moose::Meta::Role::Method::Conflicting::BEGIN@9 at line 9 of Moose/Meta/Role/Method/Conflicting.pm
# once (29µs+11µs) by Moose::Meta::TypeConstraint::Union::BEGIN@14 at line 14 of Moose/Meta/TypeConstraint/Union.pm
# once (28µs+12µs) by Moose::Meta::Role::Application::ToRole::BEGIN@13 at line 13 of Moose/Meta/Role/Application/ToRole.pm
# once (29µs+11µs) by SimpleDB::Class::Exception::BEGIN@3 at line 3 of (eval 0)[Exception/Class.pm:172] at line 172 of Exception/Class.pm
# once (29µs+11µs) by Moose::Meta::TypeConstraint::Class::BEGIN@14 at line 14 of Moose/Meta/TypeConstraint/Class.pm
# once (29µs+11µs) by Moose::Meta::TypeConstraint::Parameterizable::BEGIN@11 at line 11 of Moose/Meta/TypeConstraint/Parameterizable.pm
# once (28µs+11µs) by SimpleDB::Class::Exception::InvalidObject::BEGIN@3 at line 3 of (eval 0)[Exception/Class.pm:172] at line 172 of Exception/Class.pm
# once (28µs+11µs) by Moose::Meta::TypeConstraint::DuckType::BEGIN@17 at line 17 of Moose/Meta/TypeConstraint/DuckType.pm
# once (27µs+12µs) by Sub::Name::BEGIN@49 at line 49 of Sub/Name.pm
# once (26µs+13µs) by Moose::Meta::TypeConstraint::BEGIN@14 at line 14 of Moose/Meta/TypeConstraint.pm
# once (28µs+11µs) by SimpleDB::Client::Exception::Connection::BEGIN@3 at line 3 of (eval 0)[Exception/Class.pm:172] at line 172 of Exception/Class.pm
# once (28µs+11µs) by Moose::Meta::TypeConstraint::Enum::BEGIN@13 at line 13 of Moose/Meta/TypeConstraint/Enum.pm
# once (28µs+10µs) by DateTime::Infinite::Future::BEGIN@42 at line 42 of DateTime/Infinite.pm
# once (27µs+12µs) by Memcached::libmemcached::BEGIN@19 at line 19 of Memcached/libmemcached.pm
# once (27µs+11µs) by SimpleDB::Class::Exception::Connection::BEGIN@3 at line 3 of (eval 0)[Exception/Class.pm:172] at line 172 of Exception/Class.pm
# once (27µs+10µs) by SimpleDB::Class::Exception::InvalidParam::BEGIN@3 at line 3 of (eval 0)[Exception/Class.pm:172] at line 172 of Exception/Class.pm
# once (26µs+11µs) by Moose::Meta::TypeConstraint::Parameterized::BEGIN@15 at line 15 of Moose/Meta/TypeConstraint/Parameterized.pm
# once (26µs+10µs) by DateTime::Infinite::Past::BEGIN@63 at line 63 of DateTime/Infinite.pm
# once (26µs+10µs) by Memcached::libmemcached::API::BEGIN@23 at line 23 of Memcached/libmemcached/API.pm
# once (1.25ms+-1.25ms) by Class::MOP::Module::BEGIN@14 at line 14 of Class/MOP/Module.pm
# once (58µs+-58µs) by DateTime::Locale::root::BEGIN@25 at line 25 of DateTime/Locale/root.pm
# once (1.70ms+-1.70ms) by DateTime::Locale::en::BEGIN@25 at line 25 of DateTime/Locale/en.pm
# once (36µs+-36µs) by DateTime::TimeZone::OffsetOnly::BEGIN@9 at line 9 of DateTime/TimeZone/OffsetOnly.pm
# once (28µs+-28µs) by Class::MOP::Method::BEGIN@14 at line 14 of Class/MOP/Method.pm
# once (26µs+-26µs) by DateTime::TimeZone::UTC::BEGIN@9 at line 9 of DateTime/TimeZone/UTC.pm
# once (55µs+-55µs) by Class::MOP::Package::BEGIN@14 at line 14 of Class/MOP/Package.pm
# once (36µs+-36µs) by Class::MOP::Method::Inlined::BEGIN@13 at line 13 of Class/MOP/Method/Inlined.pm
# once (29µs+-29µs) by Class::MOP::Method::Generated::BEGIN@13 at line 13 of Class/MOP/Method/Generated.pm
# once (34µs+-34µs) by Moose::Meta::Mixin::AttributeCore::BEGIN@9 at line 9 of Moose/Meta/Mixin/AttributeCore.pm
# once (36µs+-36µs) by Moose::Meta::Method::BEGIN@10 at line 10 of Moose/Meta/Method.pm | ||||
65 | 1470 | 3.18ms | my $class = shift; | ||
66 | |||||
67 | return SUCCESS unless @_; | ||||
68 | |||||
69 | # List of base classes from which we will inherit %FIELDS. | ||||
70 | my $fields_base; | ||||
71 | |||||
72 | my $inheritor = caller(0); | ||||
73 | my @isa_classes; | ||||
74 | |||||
75 | my @bases; | ||||
76 | foreach my $base (@_) { | ||||
77 | if ( $inheritor eq $base ) { | ||||
78 | warn "Class '$inheritor' tried to inherit from itself\n"; | ||||
79 | } | ||||
80 | |||||
81 | next if grep $_->isa($base), ($inheritor, @bases); # spent 190µs making 97 calls to UNIVERSAL::isa, avg 2µs/call | ||||
82 | |||||
83 | if (has_version($base)) { # spent 512µs making 88 calls to base::has_version, avg 6µs/call | ||||
84 | ${$base.'::VERSION'} = '-1, set by base.pm' | ||||
85 | unless defined ${$base.'::VERSION'}; | ||||
86 | } | ||||
87 | else { | ||||
88 | my $sigdie; | ||||
89 | { | ||||
90 | local $SIG{__DIE__}; | ||||
91 | 1 | 1.19ms | eval "require $base"; | ||
92 | # Only ignore "Can't locate" errors from our eval require. | ||||
93 | # Other fatal errors (syntax etc) must be reported. | ||||
94 | die if $@ && $@ !~ /^Can't locate .*? at \(eval /; | ||||
95 | unless (%{"$base\::"}) { | ||||
96 | require Carp; | ||||
97 | local $" = " "; | ||||
98 | Carp::croak(<<ERROR); | ||||
99 | Base class package "$base" is empty. | ||||
100 | (Perhaps you need to 'use' the module which defines that package first, | ||||
101 | or make that module available in \@INC (\@INC contains: @INC). | ||||
102 | ERROR | ||||
103 | } | ||||
104 | $sigdie = $SIG{__DIE__} || undef; | ||||
105 | } | ||||
106 | # Make sure a global $SIG{__DIE__} makes it out of the localization. | ||||
107 | $SIG{__DIE__} = $sigdie if defined $sigdie; | ||||
108 | ${$base.'::VERSION'} = "-1, set by base.pm" | ||||
109 | unless defined ${$base.'::VERSION'}; | ||||
110 | } | ||||
111 | push @bases, $base; | ||||
112 | |||||
113 | if ( has_fields($base) || has_attr($base) ) { # spent 250µs making 88 calls to base::has_fields, avg 3µs/call
# spent 197µs making 88 calls to base::has_attr, avg 2µs/call | ||||
114 | # No multiple fields inheritance *suck* | ||||
115 | if ($fields_base) { | ||||
116 | require Carp; | ||||
117 | Carp::croak("Can't multiply inherit fields"); | ||||
118 | } else { | ||||
119 | $fields_base = $base; | ||||
120 | } | ||||
121 | } | ||||
122 | } | ||||
123 | # Save this until the end so it's all or nothing if the above loop croaks. | ||||
124 | push @{"$inheritor\::ISA"}, @isa_classes; | ||||
125 | |||||
126 | push @{"$inheritor\::ISA"}, @bases; | ||||
127 | |||||
128 | if( defined $fields_base ) { | ||||
129 | inherit_fields($inheritor, $fields_base); | ||||
130 | } | ||||
131 | } | ||||
132 | |||||
133 | |||||
134 | sub inherit_fields { | ||||
135 | my($derived, $base) = @_; | ||||
136 | |||||
137 | return SUCCESS unless $base; | ||||
138 | |||||
139 | my $battr = get_attr($base); | ||||
140 | my $dattr = get_attr($derived); | ||||
141 | my $dfields = get_fields($derived); | ||||
142 | my $bfields = get_fields($base); | ||||
143 | |||||
144 | $dattr->[0] = @$battr; | ||||
145 | |||||
146 | if( keys %$dfields ) { | ||||
147 | warn <<"END"; | ||||
148 | $derived is inheriting from $base but already has its own fields! | ||||
149 | This will cause problems. Be sure you use base BEFORE declaring fields. | ||||
150 | END | ||||
151 | |||||
152 | } | ||||
153 | |||||
154 | # Iterate through the base's fields adding all the non-private | ||||
155 | # ones to the derived class. Hang on to the original attribute | ||||
156 | # (Public, Private, etc...) and add Inherited. | ||||
157 | # This is all too complicated to do efficiently with add_fields(). | ||||
158 | while (my($k,$v) = each %$bfields) { | ||||
159 | my $fno; | ||||
160 | if ($fno = $dfields->{$k} and $fno != $v) { | ||||
161 | require Carp; | ||||
162 | Carp::croak ("Inherited fields can't override existing fields"); | ||||
163 | } | ||||
164 | |||||
165 | if( $battr->[$v] & PRIVATE ) { | ||||
166 | $dattr->[$v] = PRIVATE | INHERITED; | ||||
167 | } | ||||
168 | else { | ||||
169 | $dattr->[$v] = INHERITED | $battr->[$v]; | ||||
170 | $dfields->{$k} = $v; | ||||
171 | } | ||||
172 | } | ||||
173 | |||||
174 | foreach my $idx (1..$#{$battr}) { | ||||
175 | next if defined $dattr->[$idx]; | ||||
176 | $dattr->[$idx] = $battr->[$idx] & INHERITED; | ||||
177 | } | ||||
178 | } | ||||
179 | |||||
180 | |||||
181 | 1 | 12µs | 1; | ||
182 | |||||
183 | __END__ | ||||
184 | |||||
185 | =head1 NAME | ||||
186 | |||||
187 | base - Establish an ISA relationship with base classes at compile time | ||||
188 | |||||
189 | =head1 SYNOPSIS | ||||
190 | |||||
191 | package Baz; | ||||
192 | use base qw(Foo Bar); | ||||
193 | |||||
194 | =head1 DESCRIPTION | ||||
195 | |||||
196 | Unless you are using the C<fields> pragma, consider this module discouraged | ||||
197 | in favor of the lighter-weight C<parent>. | ||||
198 | |||||
199 | Allows you to both load one or more modules, while setting up inheritance from | ||||
200 | those modules at the same time. Roughly similar in effect to | ||||
201 | |||||
202 | package Baz; | ||||
203 | BEGIN { | ||||
204 | require Foo; | ||||
205 | require Bar; | ||||
206 | push @ISA, qw(Foo Bar); | ||||
207 | } | ||||
208 | |||||
209 | C<base> employs some heuristics to determine if a module has already been | ||||
210 | loaded, if it has it doesn't try again. If C<base> tries to C<require> the | ||||
211 | module it will not die if it cannot find the module's file, but will die on any | ||||
212 | other error. After all this, should your base class be empty, containing no | ||||
213 | symbols, it will die. This is useful for inheriting from classes in the same | ||||
214 | file as yourself, like so: | ||||
215 | |||||
216 | package Foo; | ||||
217 | sub exclaim { "I can have such a thing?!" } | ||||
218 | |||||
219 | package Bar; | ||||
220 | use base "Foo"; | ||||
221 | |||||
222 | If $VERSION is not detected even after loading it, <base> will define $VERSION | ||||
223 | in the base package, setting it to the string C<-1, set by base.pm>. | ||||
224 | |||||
225 | C<base> will also initialize the fields if one of the base classes has it. | ||||
226 | Multiple inheritance of fields is B<NOT> supported, if two or more base classes | ||||
227 | each have inheritable fields the 'base' pragma will croak. See L<fields>, | ||||
228 | L<public> and L<protected> for a description of this feature. | ||||
229 | |||||
230 | The base class' C<import> method is B<not> called. | ||||
231 | |||||
232 | |||||
233 | =head1 DIAGNOSTICS | ||||
234 | |||||
235 | =over 4 | ||||
236 | |||||
237 | =item Base class package "%s" is empty. | ||||
238 | |||||
239 | base.pm was unable to require the base package, because it was not | ||||
240 | found in your path. | ||||
241 | |||||
242 | =item Class 'Foo' tried to inherit from itself | ||||
243 | |||||
244 | Attempting to inherit from yourself generates a warning. | ||||
245 | |||||
246 | use Foo; | ||||
247 | use base 'Foo'; | ||||
248 | |||||
249 | =back | ||||
250 | |||||
251 | =head1 HISTORY | ||||
252 | |||||
253 | This module was introduced with Perl 5.004_04. | ||||
254 | |||||
255 | =head1 CAVEATS | ||||
256 | |||||
257 | Due to the limitations of the implementation, you must use | ||||
258 | base I<before> you declare any of your own fields. | ||||
259 | |||||
260 | |||||
261 | =head1 SEE ALSO | ||||
262 | |||||
263 | L<fields> | ||||
264 | |||||
265 | =cut |