<s>
Moose	B-Language
is	O
an	O
extension	O
of	O
the	O
object	B-Language
system	I-Language
of	O
the	O
Perl	B-Language
programming	I-Language
language	I-Language
.	O
</s>
<s>
Its	O
stated	O
purpose	O
is	O
to	O
bring	O
modern	O
object-oriented	B-Language
language	I-Language
features	O
to	O
Perl	B-Language
5	O
,	O
and	O
to	O
make	O
object-oriented	B-Language
Perl	I-Language
programming	I-Language
more	O
consistent	O
and	O
less	O
tedious	O
.	O
</s>
<s>
Moose	B-Language
is	O
built	O
on	O
top	O
of	O
Class::MOP	O
,	O
a	O
metaobject	O
protocol	O
(	O
a.k.a.	O
</s>
<s>
Using	O
the	O
MOP	O
,	O
Moose	B-Language
provides	O
complete	O
introspection	B-Application
for	O
all	O
Moose-using	O
classes	O
.	O
</s>
<s>
Moose	B-Language
allows	O
a	O
programmer	O
to	O
create	O
classes	O
:	O
</s>
<s>
A	O
class	O
has	O
zero	O
or	O
more	O
attributes	B-General_Concept
.	O
</s>
<s>
A	O
class	O
has	O
zero	O
or	O
more	O
methods	B-Language
.	O
</s>
<s>
A	O
class	O
inherits	B-Language
from	O
its	O
superclass(es )	O
.	O
</s>
<s>
Moose	B-Language
supports	O
multiple	B-Application
inheritance	I-Application
.	O
</s>
<s>
These	O
modifiers	O
can	O
apply	O
to	O
its	O
own	O
methods	B-Language
,	O
methods	B-Language
that	O
are	O
inherited	O
from	O
its	O
ancestors	O
or	O
methods	B-Language
that	O
are	O
provided	O
by	O
roles	O
.	O
</s>
<s>
A	O
class	O
has	O
a	O
constructor	O
and	O
a	O
destructor	B-Language
.	O
</s>
<s>
A	O
class	O
has	O
a	O
metaclass	B-Language
.	O
</s>
<s>
An	O
attribute	O
's	O
characteristics	O
may	O
include	O
a	O
read/write	O
flag	O
,	O
a	O
type	O
,	O
accessor	O
method	B-Language
names	I-Language
,	O
delegations	O
,	O
a	O
default	B-General_Concept
value	O
and	O
lazy	O
initialization	O
.	O
</s>
<s>
Roles	O
in	O
Moose	B-Language
are	O
based	O
on	O
traits	O
.	O
</s>
<s>
They	O
perform	O
a	O
similar	O
task	O
as	O
mixins	B-Language
,	O
but	O
are	O
composed	O
horizontally	O
rather	O
than	O
inherited	O
.	O
</s>
<s>
They	O
are	O
also	O
somewhat	O
like	O
interfaces	B-Application
,	O
but	O
unlike	O
some	O
implementations	O
of	O
interfaces	B-Application
they	O
can	O
provide	O
a	O
default	B-General_Concept
implementation	O
.	O
</s>
<s>
A	O
role	O
has	O
zero	O
or	O
more	O
attributes	B-General_Concept
.	O
</s>
<s>
A	O
role	O
has	O
zero	O
or	O
more	O
methods	B-Language
.	O
</s>
<s>
A	O
role	O
has	O
zero	O
or	O
more	O
required	O
methods	B-Language
.	O
</s>
<s>
There	O
are	O
a	O
number	O
of	O
Moose	B-Language
extension	O
modules	O
on	O
CPAN	B-Language
.	O
</s>
<s>
Most	O
of	O
them	O
can	O
be	O
optionally	O
installed	O
with	O
the	O
Task::Moose	O
module	O
.	O
</s>
<s>
The	O
clear( )	O
method	O
on	O
the	O
other	O
hand	O
is	O
not	O
replaced	O
but	O
extended	O
in	O
the	O
subclass	O
,	O
so	O
both	O
methods	B-Language
are	O
run	O
in	O
the	O
correct	O
order	O
.	O
</s>
