<s>
In	O
computer	B-General_Concept
programming	I-General_Concept
,	O
a	O
standard	B-Library
library	I-Library
is	O
the	O
library	B-Library
made	O
available	O
across	O
implementations	B-Application
of	O
a	O
programming	O
language	O
.	O
</s>
<s>
These	O
libraries	O
are	O
conventionally	O
described	O
in	O
programming	O
language	O
specifications	O
;	O
however	O
,	O
contents	O
of	O
a	O
language	O
's	O
associated	O
library	B-Library
may	O
also	O
be	O
determined	O
(	O
in	O
part	O
or	O
whole	O
)	O
by	O
more	O
informal	O
practices	O
of	O
a	O
language	O
's	O
community	O
.	O
</s>
<s>
A	O
language	O
's	O
standard	B-Library
library	I-Library
is	O
often	O
treated	O
as	O
part	O
of	O
the	O
language	O
by	O
its	O
users	O
,	O
although	O
the	O
designers	O
may	O
have	O
treated	O
it	O
as	O
a	O
separate	O
entity	O
.	O
</s>
<s>
Many	O
language	O
specifications	O
define	O
a	O
core	O
set	O
that	O
must	O
be	O
made	O
available	O
in	O
all	O
implementations	B-Application
,	O
in	O
addition	O
to	O
other	O
portions	O
which	O
may	O
be	O
optionally	O
implemented	O
.	O
</s>
<s>
Indeed	O
,	O
some	O
languages	O
are	O
designed	O
so	O
that	O
the	O
meanings	O
of	O
certain	O
syntactic	O
constructs	O
cannot	O
even	O
be	O
described	O
without	O
referring	O
to	O
the	O
core	O
library	B-Library
.	O
</s>
<s>
For	O
example	O
,	O
in	O
Java	B-Device
,	O
a	O
string	B-Language
literal	I-Language
is	O
defined	O
as	O
an	O
instance	O
of	O
the	O
java.lang.String	O
class	O
;	O
similarly	O
,	O
in	O
Smalltalk	B-Application
,	O
an	O
anonymous	O
function	O
expression	O
(	O
a	O
"	O
block	O
"	O
)	O
constructs	O
an	O
instance	O
of	O
the	O
library	B-Library
's	O
BlockContext	O
class	O
.	O
</s>
<s>
Conversely	O
,	O
Scheme	B-Language
contains	O
multiple	O
coherent	O
subsets	O
that	O
suffice	O
to	O
construct	O
the	O
rest	O
of	O
the	O
language	O
as	O
library	B-Library
macros	O
,	O
and	O
so	O
the	O
language	O
designers	O
do	O
not	O
even	O
bother	O
to	O
say	O
which	O
portions	O
of	O
the	O
language	O
must	O
be	O
implemented	O
as	O
language	O
constructs	O
,	O
and	O
which	O
must	O
be	O
implemented	O
as	O
parts	O
of	O
a	O
library	B-Library
.	O
</s>
<s>
Standard	B-Library
libraries	I-Library
typically	O
include	O
definitions	O
for	O
commonly	O
used	O
algorithms	O
,	O
data	B-General_Concept
structures	I-General_Concept
,	O
and	O
mechanisms	O
for	O
input	O
and	O
output	O
.	O
</s>
<s>
Depending	O
on	O
the	O
constructs	O
made	O
available	O
by	O
the	O
host	O
language	O
,	O
a	O
standard	B-Library
library	I-Library
may	O
include	O
:	O
</s>
<s>
Most	O
standard	B-Library
libraries	I-Library
include	O
definitions	O
for	O
at	O
least	O
the	O
following	O
commonly	O
used	O
facilities	O
:	O
</s>
<s>
Philosophies	O
of	O
standard	B-Library
library	I-Library
design	O
vary	O
widely	O
.	O
</s>
<s>
For	O
example	O
,	O
Bjarne	O
Stroustrup	O
,	O
designer	O
of	O
C++	B-Language
,	O
writes	O
:	O
</s>
<s>
This	O
suggests	O
a	O
relatively	O
small	O
standard	B-Library
library	I-Library
,	O
containing	O
only	O
the	O
constructs	O
that	O
"	O
every	O
programmer	B-Application
"	O
might	O
reasonably	O
require	O
when	O
building	O
a	O
large	O
collection	O
of	O
software	O
.	O
</s>
<s>
This	O
is	O
the	O
philosophy	O
that	O
is	O
used	O
in	O
the	O
C	B-Language
and	O
C++	B-Language
standard	I-Language
libraries	I-Language
.	O
</s>
<s>
By	O
contrast	O
,	O
Guido	O
van	O
Rossum	O
,	O
designer	O
of	O
Python	B-Language
,	O
has	O
embraced	O
a	O
much	O
more	O
inclusive	O
vision	O
of	O
the	O
standard	B-Library
library	I-Library
Python	B-Language
offers	O
us	O
easy-to-code	O
,	O
object-oriented	O
,	O
high-level	O
language	O
means	O
.	O
</s>
<s>
In	O
the	O
Python	B-Language
tutorial	O
,	O
he	O
writes	O
:	O
</s>
<s>
Van	O
Rossum	O
goes	O
on	O
to	O
list	O
libraries	O
for	O
processing	O
XML	B-Protocol
,	O
XML-RPC	B-Protocol
,	O
email	O
messages	O
,	O
and	O
localization	O
,	O
facilities	O
that	O
the	O
C++	B-Language
standard	I-Language
library	I-Language
omits	O
.	O
</s>
<s>
This	O
other	O
philosophy	O
is	O
often	O
found	O
in	O
scripting	B-Language
languages	I-Language
(	O
as	O
in	O
Python	B-Language
or	O
Ruby	B-Language
)	O
or	O
languages	O
that	O
use	O
a	O
virtual	B-Architecture
machine	I-Architecture
,	O
such	O
as	O
Java	B-Device
or	O
the	O
.NET	B-Application
Framework	I-Application
languages	O
.	O
</s>
<s>
In	O
C++	B-Language
,	O
such	O
facilities	O
are	O
not	O
part	O
of	O
the	O
standard	B-Library
library	I-Library
,	O
but	O
instead	O
other	O
libraries	O
,	O
such	O
as	O
Boost	B-Language
.	O
</s>
