<s>
Shed	B-Application
Skin	I-Application
is	O
an	O
experimental	O
restricted-Python	O
(	O
3.8	O
+	O
)	O
to	O
C++	B-Language
programming	I-Language
language	I-Language
compiler	B-Language
.	O
</s>
<s>
It	O
can	O
translate	O
pure	O
,	O
but	O
implicitly	O
statically	O
typed	O
Python	B-Language
programs	I-Language
into	O
optimized	O
C++	B-Language
.	O
</s>
<s>
It	O
can	O
generate	O
stand-alone	O
programs	O
or	O
extension	O
modules	O
that	O
can	O
be	O
imported	O
and	O
used	O
in	O
larger	O
Python	B-Language
programs	I-Language
.	O
</s>
<s>
Shed	B-Application
Skin	I-Application
is	O
an	O
open	O
source	O
project	O
with	O
contributions	O
from	O
many	O
people	O
,	O
however	O
the	O
main	O
author	O
is	O
Mark	O
Dufour	O
.	O
</s>
<s>
Work	O
has	O
been	O
going	O
into	O
Shed	B-Application
Skin	I-Application
since	O
2005	O
.	O
</s>
<s>
Besides	O
the	O
typing	O
restriction	O
,	O
programs	O
cannot	O
freely	O
use	O
the	O
Python	B-Language
standard	O
library	O
,	O
although	O
about	O
20	O
common	O
modules	O
,	O
such	O
as	O
random	O
,	O
itertools	O
and	O
re	O
(	O
regular	B-Language
expressions	I-Language
)	O
,	O
are	O
supported	O
as	O
of	O
2011	O
.	O
</s>
<s>
Also	O
,	O
not	O
all	O
Python	B-Language
features	O
,	O
such	O
as	O
nested	O
functions	O
and	O
variable	O
numbers	O
of	O
arguments	O
,	O
are	O
supported	O
.	O
</s>
<s>
As	O
of	O
June	O
2016	O
for	O
a	O
set	O
of	O
75	O
non-trivial	O
test	O
programs	O
(	O
at	O
over	O
25,000	O
lines	O
of	O
code	O
in	O
total	O
)	O
,	O
measurements	O
show	O
a	O
typical	O
speedup	O
of	O
2-20	O
times	O
over	O
Psyco	B-Language
,	O
and	O
2-200	O
times	O
over	O
CPython	B-Language
.	O
</s>
<s>
Shed	B-Application
Skin	I-Application
is	O
still	O
in	O
an	O
early	O
stage	O
of	O
development	O
,	O
so	O
many	O
other	O
programs	O
will	O
not	O
compile	B-Language
unmodified	O
.	O
</s>
<s>
Shed	B-Application
Skin	I-Application
can	O
be	O
used	O
to	O
generate	O
standalone	O
executables	O
which	O
need	O
only	O
the	O
C++	B-Language
runtime	O
libraries	O
.	O
</s>
<s>
It	O
can	O
also	O
be	O
used	O
to	O
generate	O
CPython	B-Language
modules	O
.	O
</s>
<s>
This	O
allows	O
compiling	B-Language
parts	O
of	O
larger	O
programs	O
with	O
Shed	B-Application
Skin	I-Application
,	O
while	O
running	O
the	O
other	O
parts	O
using	O
regular	O
CPython	B-Language
.	O
</s>
<s>
Another	O
use	O
has	O
been	O
to	O
wrap	O
C++	B-Language
classes	O
using	O
Shed	B-Application
Skin	I-Application
to	O
allow	O
C++	B-Language
classes	O
to	O
be	O
used	O
as	O
Python	B-Language
classes	O
.	O
</s>
<s>
The	O
license	O
of	O
the	O
Shed	B-Application
Skin	I-Application
source	O
code	O
is	O
under	O
two	O
parts	O
.	O
</s>
<s>
The	O
main	O
compiler	B-Language
code	O
is	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
(	O
GPL	B-License
)	O
.	O
</s>
<s>
The	O
supporting	O
code	O
that	O
it	O
uses	O
as	O
a	O
run	O
time	O
library	O
is	O
under	O
a	O
BSD	B-Operating_System
or	O
MIT	B-License
license	I-License
depending	O
on	O
the	O
module	O
.	O
</s>
<s>
This	O
allows	O
compiling	B-Language
both	O
GPL	B-License
and	O
non-GPL	O
programs	O
.	O
</s>
<s>
Shed	B-Application
Skin	I-Application
combines	O
Ole	O
Agesen	O
's	O
Cartesian	O
Product	O
Algorithm	O
(	O
CPA	O
)	O
with	O
the	O
data-polymorphic	O
part	O
of	O
John	O
Plevyak	O
's	O
Iterative	O
Flow	O
Analysis	O
(	O
IFA	O
)	O
.	O
</s>
<s>
This	O
allows	O
Shed	B-Application
Skin	I-Application
to	O
do	O
type	O
inference	O
on	O
larger	O
programs	O
than	O
previously	O
.	O
</s>
<s>
Several	O
of	O
these	O
,	O
such	O
as	O
os.path	O
,	O
were	O
compiled	B-Language
to	O
C++	B-Language
using	O
Shed	B-Application
Skin	I-Application
.	O
</s>
<s>
Note	O
that	O
any	O
other	O
module	O
,	O
such	O
as	O
pygame	O
,	O
pyqt	O
or	O
pickle	O
,	O
may	O
be	O
used	O
in	O
combination	O
with	O
a	O
Shed	B-Application
Skin	I-Application
generated	O
.	O
</s>
<s>
For	O
examples	O
of	O
this	O
,	O
see	O
the	O
Shed	B-Application
Skin	I-Application
.	O
</s>
