<s>
PyPy	B-Language
(	O
)	O
is	O
an	O
implementation	O
of	O
the	O
Python	B-Language
programming	I-Language
language	I-Language
.	O
</s>
<s>
PyPy	B-Language
often	O
runs	O
faster	O
than	O
the	O
standard	O
implementation	O
CPython	B-Language
because	O
PyPy	B-Language
uses	O
a	O
just-in-time	O
compiler	B-Language
.	O
</s>
<s>
Most	O
Python	B-Language
code	I-Language
runs	O
well	O
on	O
PyPy	B-Language
except	O
for	O
code	O
that	O
depends	O
on	O
CPython	B-Language
extensions	O
,	O
which	O
either	O
does	O
not	O
work	O
or	O
incurs	O
some	O
overhead	O
when	O
run	O
in	O
PyPy	B-Language
.	O
</s>
<s>
Internally	O
,	O
PyPy	B-Language
uses	O
a	O
technique	O
known	O
as	O
meta-tracing	O
,	O
which	O
transforms	O
an	O
interpreter	B-Application
into	O
a	O
tracing	B-Application
just-in-time	I-Application
compiler	I-Application
.	O
</s>
<s>
Since	O
interpreters	B-Application
are	O
usually	O
easier	O
to	O
write	O
than	O
compilers	B-Language
,	O
but	O
run	O
slower	O
,	O
this	O
technique	O
can	O
make	O
it	O
easier	O
to	O
produce	O
efficient	O
implementations	O
of	O
programming	O
languages	O
.	O
</s>
<s>
PyPy	B-Language
's	O
meta-tracing	O
toolchain	B-General_Concept
is	O
called	O
RPython	B-Language
.	O
</s>
<s>
PyPy	B-Language
does	O
not	O
have	O
full	O
compatibility	O
with	O
more	O
recent	O
versions	O
of	O
the	O
CPython	B-Language
ecosystem	O
.	O
</s>
<s>
While	O
it	O
claims	O
compatibility	O
with	O
Python	B-Language
2.7	O
,	O
3.7	O
,	O
3.8	O
and	O
3.9	O
(	O
"	O
a	O
drop-in	O
replacement	O
for	O
CPython	B-Language
"	O
)	O
,	O
it	O
loses	O
out	O
on	O
newer	O
features	O
and	O
syntax	O
in	O
Python	B-Language
3.10	O
,	O
such	O
as	O
syntax	O
for	O
pattern	B-Language
matching	I-Language
.	O
</s>
<s>
PyPy	B-Language
aims	O
to	O
provide	O
a	O
common	O
translation	O
and	O
support	O
framework	B-Architecture
for	O
producing	O
implementations	O
of	O
dynamic	B-Language
languages	I-Language
,	O
emphasizing	O
a	O
clean	O
separation	O
between	O
language	O
specification	O
and	O
implementation	O
aspects	O
.	O
</s>
<s>
It	O
also	O
aims	O
to	O
provide	O
a	O
compliant	O
,	O
flexible	O
and	O
fast	O
implementation	O
of	O
the	O
Python	B-Language
programming	I-Language
language	I-Language
using	O
the	O
above	O
framework	B-Architecture
to	O
enable	O
new	O
advanced	O
features	O
without	O
having	O
to	O
encode	O
low-level	O
details	O
into	O
it	O
.	O
</s>
<s>
The	O
PyPy	B-Language
interpreter	B-Application
itself	O
is	O
written	O
in	O
a	O
restricted	O
subset	O
of	O
Python	B-Language
called	O
RPython	B-Language
(	O
Restricted	O
Python	B-Language
)	O
.	O
</s>
<s>
RPython	B-Language
puts	O
some	O
constraints	O
on	O
the	O
Python	B-Language
language	I-Language
such	O
that	O
a	O
variable	O
's	O
type	O
can	O
be	O
inferred	O
at	O
compile	B-Language
time	O
.	O
</s>
<s>
The	O
PyPy	B-Language
project	O
has	O
developed	O
a	O
toolchain	B-General_Concept
that	O
analyzes	O
RPython	B-Language
code	O
and	O
translates	O
it	O
into	O
a	O
form	O
of	O
byte	O
code	O
,	O
which	O
can	O
be	O
lowered	O
into	O
C	B-Language
.	O
There	O
used	O
to	O
be	O
other	O
backends	B-Architecture
in	O
addition	O
to	O
C	B-Language
:	O
Java	B-Language
,	O
C#	B-Application
,	O
and	O
Javascript	B-Language
,	O
but	O
those	O
suffered	O
from	O
bitrot	O
and	O
have	O
been	O
removed	O
.	O
</s>
<s>
Thus	O
,	O
the	O
recursive	O
logo	O
of	O
PyPy	B-Language
is	O
a	O
snake	B-General_Concept
swallowing	I-General_Concept
itself	I-General_Concept
since	O
the	O
RPython	B-Language
is	O
translated	O
by	O
a	O
Python	B-Language
interpreter	B-Application
.	O
</s>
<s>
The	O
code	O
can	O
also	O
be	O
run	O
untranslated	O
for	O
testing	O
and	O
analysis	O
,	O
which	O
provides	O
a	O
nice	O
test-bed	O
for	O
research	O
into	O
dynamic	B-Language
languages	I-Language
.	O
</s>
<s>
It	O
allows	O
for	O
pluggable	O
garbage	B-General_Concept
collectors	I-General_Concept
,	O
as	O
well	O
as	O
optionally	O
enabling	O
Stackless	B-Operating_System
Python	I-Operating_System
features	O
.	O
</s>
<s>
Finally	O
,	O
it	O
includes	O
a	O
just-in-time	O
(	O
JIT	O
)	O
generator	O
that	O
builds	O
a	O
just-in-time	O
compiler	B-Language
into	O
the	O
interpreter	B-Application
,	O
given	O
a	O
few	O
annotations	O
in	O
the	O
interpreter	B-Application
source	O
code	O
.	O
</s>
<s>
The	O
generated	O
JIT	O
compiler	B-Language
is	O
a	O
tracing	B-Application
JIT	I-Application
.	O
</s>
<s>
RPython	B-Language
is	O
now	O
also	O
used	O
to	O
write	O
non-Python	O
language	O
implementations	O
,	O
such	O
as	O
Pixie	O
.	O
</s>
<s>
PyPy	B-Language
as	O
of	O
version	O
7.3.7	O
is	O
compatible	O
with	O
three	O
CPython	B-Language
versions	O
:	O
2.7	O
,	O
3.7	O
and	O
3.8	O
.	O
</s>
<s>
The	O
first	O
PyPy	B-Language
version	O
compatible	O
with	O
CPython	B-Language
v3	O
is	O
PyPy	B-Language
v2.3.1	O
(	O
2014	O
)	O
.	O
</s>
<s>
The	O
PyPy	B-Language
interpreter	B-Application
compatible	O
with	O
CPython	B-Language
v3	O
is	O
also	O
known	O
as	O
PyPy3	O
.	O
</s>
<s>
PyPy	B-Language
has	O
JIT	O
compilation	B-Language
support	O
on	O
32-bit/64	O
-bit	O
x86	B-Operating_System
and	O
32-bit/64	O
-bit	O
ARM	B-Architecture
processors	I-Architecture
.	O
</s>
<s>
It	O
is	O
tested	O
nightly	O
on	O
Windows	O
,	O
Linux	O
,	O
OpenBSD	O
and	O
Mac	O
OS	O
X	O
.	O
PyPy	B-Language
is	O
able	O
to	O
run	O
pure	O
Python	B-Language
software	O
that	O
does	O
not	O
rely	O
on	O
implementation-specific	O
features	O
.	O
</s>
<s>
There	O
is	O
a	O
compatibility	O
layer	O
for	O
CPython	B-Language
C	B-Language
API	O
extensions	O
called	O
CPyExt	O
,	O
but	O
it	O
is	O
incomplete	O
and	O
experimental	O
.	O
</s>
<s>
The	O
preferred	O
way	O
of	O
interfacing	O
with	O
C	B-Language
shared	O
libraries	O
is	O
through	O
the	O
built-in	O
C	B-Language
foreign	B-Application
function	I-Application
interface	I-Application
(	O
CFFI	O
)	O
or	O
ctypes	B-Application
libraries	O
.	O
</s>
<s>
PyPy	B-Language
is	O
a	O
followup	O
to	O
the	O
Psyco	B-Language
project	O
,	O
a	O
just-in-time	O
specializing	B-Algorithm
compiler	I-Algorithm
for	O
Python	B-Language
,	O
developed	O
by	O
Armin	O
Rigo	O
between	O
2002	O
and	O
2010	O
.	O
</s>
<s>
PyPy	B-Language
's	O
aim	O
is	O
to	O
have	O
a	O
just-in-time	O
specializing	B-Algorithm
compiler	I-Algorithm
with	O
scope	O
,	O
which	O
was	O
not	O
available	O
for	O
Psyco	B-Language
.	O
</s>
<s>
Initially	O
,	O
the	O
RPython	B-Language
could	O
also	O
be	O
compiled	B-Language
into	O
Java	B-Language
bytecode	I-Language
,	O
CIL	O
and	O
JavaScript	B-Language
,	O
but	O
these	O
backends	B-Architecture
were	O
removed	O
due	O
to	O
lack	O
of	O
interest	O
.	O
</s>
<s>
PyPy	B-Language
was	O
initially	O
a	O
research	O
and	O
development-oriented	O
project	O
.	O
</s>
<s>
Reaching	O
a	O
mature	O
state	O
of	O
development	O
and	O
an	O
official	O
1.0	O
release	O
in	O
mid-2007	O
,	O
its	O
next	O
focus	O
was	O
on	O
releasing	O
a	O
production-ready	O
version	O
with	O
more	O
CPython	B-Language
compatibility	O
.	O
</s>
<s>
Many	O
of	O
PyPy	B-Language
's	O
changes	O
have	O
been	O
made	O
during	O
coding	O
sprints	O
.	O
</s>
<s>
In	O
August	O
2008	O
,	O
PyPy	B-Language
was	O
able	O
to	O
run	O
some	O
popular	O
Python	B-Language
libraries	O
like	O
Pylons	O
,	O
Pyglet	B-Library
,	O
Nevow	B-Language
and	O
Django	B-Language
.	O
</s>
<s>
On	O
12	O
March	O
2010	O
,	O
PyPy	B-Language
1.2	O
was	O
released	O
,	O
focusing	O
on	O
speed	O
.	O
</s>
<s>
It	O
included	O
a	O
working	O
,	O
though	O
not	O
yet	O
stable	O
,	O
just-in-time	O
compiler	B-Language
.	O
</s>
<s>
On	O
30	O
April	O
2011	O
,	O
PyPy	B-Language
version	O
1.5	O
was	O
released	O
,	O
which	O
reached	O
compatibility	O
with	O
CPython	B-Language
2.7	O
.	O
</s>
<s>
On	O
9	O
May	O
2013	O
,	O
PyPy	B-Language
2.0	O
was	O
released	O
,	O
which	O
introduced	O
alpha-quality	O
support	O
for	O
JIT	O
compilation	B-Language
on	O
ARMv6	O
and	O
ARMv7	O
JIT	O
,	O
and	O
included	O
CFFI	O
in	O
the	O
standard	O
library	O
.	O
</s>
<s>
On	O
20	O
June	O
2014	O
,	O
PyPy3	O
was	O
declared	O
stable	O
and	O
introduced	O
compatibility	O
with	O
the	O
more	O
modern	O
Python	B-Language
3	O
.	O
</s>
<s>
It	O
was	O
released	O
alongside	O
PyPy	B-Language
2.3.1	O
and	O
bears	O
the	O
same	O
version	O
number	O
.	O
</s>
<s>
On	O
21	O
March	O
2017	O
,	O
the	O
PyPy	B-Language
project	O
released	O
version	O
5.7	O
of	O
both	O
PyPy	B-Language
and	O
PyPy3	O
,	O
with	O
the	O
latter	O
introducing	O
beta-quality	O
support	O
for	O
Python	B-Language
3.5	O
.	O
</s>
<s>
On	O
26	O
April	O
2018	O
,	O
version	O
6.0	O
was	O
released	O
,	O
with	O
support	O
for	O
Python	B-Language
2.7	O
and	O
3.5	O
(	O
still	O
beta-quality	O
on	O
Windows	O
)	O
.	O
</s>
<s>
On	O
11	O
February	O
2019	O
,	O
version	O
7.0	O
was	O
released	O
,	O
with	O
support	O
for	O
Python	B-Language
2.7	O
and	O
3.5	O
.	O
</s>
<s>
On	O
14	O
October	O
2019	O
,	O
version	O
7.2	O
was	O
released	O
,	O
with	O
support	O
for	O
Python	B-Language
3.6.9	O
.	O
</s>
<s>
On	O
24	O
December	O
2019	O
,	O
version	O
7.3	O
was	O
released	O
,	O
with	O
support	O
for	O
Python	B-Language
3.6.9	O
.	O
</s>
<s>
On	O
16	O
February	O
2020	O
,	O
the	O
PyPy	B-Language
team	O
announced	O
the	O
move	O
of	O
the	O
source	O
code	O
hosting	O
from	O
Bitbucket	B-Protocol
to	O
heptapod.net	O
with	O
the	O
repositories	O
of	O
the	O
CFFI	O
(	O
C	B-Language
Foreign	B-Application
Function	I-Application
Interface	I-Application
)	O
project	O
.	O
</s>
<s>
PyPy	B-Language
was	O
funded	O
by	O
the	O
European	O
Union	O
being	O
a	O
Specific	O
Targeted	O
Research	O
Project	O
between	O
December	O
2004	O
and	O
March	O
2007	O
.	O
</s>
<s>
In	O
June	O
2008	O
,	O
PyPy	B-Language
announced	O
funding	O
being	O
part	O
of	O
the	B-Application
Google	I-Application
Open	O
Source	O
programs	O
and	O
has	O
agreed	O
to	O
focus	O
on	O
making	O
PyPy	B-Language
more	O
compatible	O
with	O
CPython	B-Language
.	O
</s>
<s>
In	O
2009	O
Eurostars	O
,	O
a	O
European	O
Union	O
funding	O
agency	O
specially	O
focused	O
on	O
SMEs	O
,	O
accepted	O
a	O
proposal	O
from	O
PyPy	B-Language
project	O
members	O
titled	O
"	O
PYJIT	O
–	O
a	O
fast	O
and	O
flexible	O
toolkit	O
for	O
dynamic	B-Language
programming	I-Language
languages	I-Language
based	O
on	O
PyPy	B-Language
"	O
.	O
</s>
<s>
At	O
PyCon	B-Language
US	O
2011	O
,	O
the	O
Python	B-Application
Software	I-Application
Foundation	I-Application
provided	O
a	O
$	O
10,000	O
grant	O
for	O
PyPy	B-Language
to	O
continue	O
work	O
on	O
performance	O
and	O
compatibility	O
with	O
newer	O
versions	O
of	O
the	O
language	O
.	O
</s>
<s>
The	O
port	O
to	O
ARM	B-Architecture
architecture	I-Architecture
was	O
sponsored	O
in	O
part	O
by	O
the	O
Raspberry	O
Pi	O
Foundation	O
.	O
</s>
<s>
The	O
PyPy	B-Language
project	O
also	O
accepts	O
donations	O
through	O
its	O
status	O
blog	O
pages	O
.	O
</s>
<s>
As	O
of	O
2013	O
,	O
a	O
variety	O
of	O
sub-projects	O
had	O
funding	O
:	O
Python	B-Language
3	O
version	O
compatibility	O
,	O
built-in	O
optimized	O
NumPy	B-Application
support	O
for	O
numerical	O
calculations	O
and	O
software	B-Operating_System
transactional	I-Operating_System
memory	I-Operating_System
support	O
to	O
allow	O
better	O
parallelism	O
.	O
</s>
