<s>
.NET	B-Application
Compiler	I-Application
Platform	I-Application
,	O
also	O
known	O
by	O
its	O
codename	O
Roslyn	B-Application
,	O
is	O
a	O
set	O
of	O
open-source	B-Application
compilers	B-Language
and	O
code	O
analysis	O
APIs	B-Application
for	O
C#	B-Application
and	O
Visual	B-Language
Basic	I-Language
(	O
VB.NET	B-Language
)	O
languages	O
from	O
Microsoft	O
.	O
</s>
<s>
The	O
project	O
notably	O
includes	O
self-hosting	O
versions	O
of	O
the	O
C#	B-Application
and	O
VB.NET	B-Language
compilers	B-Language
–	O
compilers	B-Language
written	O
in	O
the	O
languages	O
themselves	O
.	O
</s>
<s>
The	O
compilers	B-Language
are	O
available	O
via	O
the	O
traditional	O
command-line	O
programs	O
but	O
also	O
as	O
APIs	B-Application
available	O
natively	O
from	O
within	O
.NET	B-Application
code	O
.	O
</s>
<s>
Roslyn	B-Application
exposes	O
modules	O
for	O
syntactic	O
(	O
lexical	B-Application
)	O
analysis	O
of	O
code	O
,	O
semantic	O
analysis	O
,	O
dynamic	O
compilation	B-Language
to	O
CIL	O
,	O
and	O
code	O
emission	O
.	O
</s>
<s>
Features	O
of	O
Roslyn	B-Application
include	O
:	O
</s>
<s>
Compilers	B-Language
for	O
the	O
C#	B-Application
and	O
Visual	B-Language
Basic	I-Language
languages	O
exposed	O
as	O
services	O
via	O
APIs	B-Application
.	O
</s>
<s>
APIs	B-Application
for	O
code	O
analysis	O
and	O
refactoring	O
.	O
</s>
<s>
The	O
code	O
name	O
"	O
Roslyn	B-Application
"	O
was	O
first	O
written	O
by	O
Eric	O
Lippert	O
(	O
a	O
former	O
Microsoft	O
engineer	O
)	O
in	O
a	O
post	O
that	O
he	O
published	O
in	O
2010	O
to	O
hire	O
developers	O
for	O
a	O
new	O
project	O
.	O
</s>
<s>
He	O
first	O
said	O
that	O
the	O
origin	O
of	O
the	O
name	O
was	O
because	O
of	O
Roslyn	B-Application
,	O
Washington	O
,	O
but	O
later	O
in	O
the	O
post	O
he	O
speaks	O
ironically	O
about	O
the	O
"	O
northern	O
exposure	O
"	O
of	O
its	O
office	O
;	O
the	O
city	O
of	O
Roslyn	B-Application
was	O
one	O
of	O
the	O
places	O
where	O
the	O
television	O
series	O
Northern	O
Exposure	O
was	O
filmed	O
.	O
</s>
<s>
It	O
installed	O
as	O
an	O
extension	O
to	O
Visual	B-Application
Studio	I-Application
2010	O
SP1	O
.	O
</s>
<s>
The	O
CTP	O
was	O
updated	O
in	O
September	O
2012	O
to	O
include	O
many	O
updates	O
to	O
the	O
Roslyn	B-Application
APIs	B-Application
introduced	O
in	O
the	O
June	O
2012	O
and	O
October	O
2011	O
CTPs	O
,	O
including	O
breaking	O
changes	O
.	O
</s>
<s>
While	O
the	O
June	O
2012	O
CTP	O
API	B-Application
is	O
complete	O
for	O
the	O
compilers	B-Language
,	O
not	O
all	O
features	O
were	O
implemented	O
for	O
the	O
C#	B-Application
and	O
VB.NET	B-Language
languages	O
.	O
</s>
<s>
At	O
the	O
Build	O
2014	O
conference	O
in	O
San	O
Francisco	O
April	O
2014	O
,	O
Microsoft	O
made	O
the	O
"	O
Roslyn	B-Application
"	O
project	O
open-source	B-Application
and	O
released	O
a	O
preview	O
of	O
the	O
language	O
integration	O
for	O
Visual	B-Application
Studio	I-Application
2013	O
.	O
</s>
<s>
As	O
of	O
April	O
3	O
,	O
2014	O
,	O
Roslyn	B-Application
is	O
under	O
the	O
Apache	B-Application
License	I-Application
2.0	O
.	O
</s>
<s>
The	O
project	O
was	O
effectively	O
transferred	O
under	O
the	O
stewardship	O
of	O
the	O
newly	O
founded	O
.NET	B-Application
Foundation	O
.	O
</s>
<s>
At	O
the	O
same	O
conference	O
,	O
Xamarin	B-Application
announced	O
that	O
they	O
are	O
working	O
on	O
integrating	O
the	O
new	O
compilers	B-Language
and	O
tools	O
in	O
Xamarin	B-Application
Studio	O
.	O
</s>
<s>
The	O
compilers	B-Language
were	O
not	O
feature-complete	O
in	O
this	O
release	O
.	O
</s>
<s>
Each	O
of	O
the	O
compilers	B-Language
contains	O
features	O
that	O
are	O
planned	O
for	O
the	O
coming	O
language	O
versions	O
(	O
C#	B-Application
6	O
and	O
Visual	B-Language
Basic.NET	I-Language
14	O
)	O
.	O
</s>
<s>
The	O
APIs	B-Application
are	O
also	O
available	O
through	O
the	O
NuGet	B-Application
package	I-Application
manager	I-Application
.	O
</s>
<s>
Roslyn	B-Application
's	O
first	O
release	O
to	O
manufacturing	O
(	O
RTM	O
)	O
was	O
with	O
Visual	B-Application
Studio	I-Application
2015	O
.	O
</s>
<s>
Roslyn	B-Application
currently	O
only	O
supports	O
VB	O
and	O
C#	B-Application
,	O
and	O
the	O
compilers	B-Language
were	O
written	O
in	O
their	O
respective	O
languages	O
.	O
</s>
<s>
In	O
January	O
2015	O
,	O
Microsoft	O
moved	O
the	O
Roslyn	B-Application
source	O
code	O
from	O
CodePlex	B-Protocol
to	O
GitHub	B-Application
.	O
</s>
<s>
Traditionally	O
.NET	B-Application
compilers	B-Language
have	O
been	O
a	O
black	O
box	O
for	O
application	O
developers	O
.	O
</s>
<s>
With	O
increasing	O
complexity	O
and	O
demands	O
for	O
source	O
code	O
analysis	O
in	O
modern	O
integrated	B-Application
development	I-Application
environments	I-Application
,	O
however	O
,	O
compilers	B-Language
need	O
to	O
expose	O
application	B-Application
programming	I-Application
interfaces	I-Application
(	O
APIs	B-Application
)	O
that	O
will	O
help	O
developers	O
to	O
directly	O
perform	O
phases	O
of	O
compilation	B-Language
such	O
as	O
lexical	B-Application
and	O
syntactic	O
structure	O
analysis	O
of	O
source	O
code	O
.	O
</s>
<s>
Roslyn	B-Application
was	O
designed	O
with	O
that	O
intent	O
from	O
the	O
beginning	O
.	O
</s>
<s>
APIs	B-Application
of	O
Roslyn	B-Application
are	O
of	O
three	O
types	O
:	O
feature	O
APIs	B-Application
,	O
work-space	O
APIs	B-Application
and	O
compiler	B-Language
APIs	B-Application
.	O
</s>
<s>
Feature	O
APIs	B-Application
allow	O
source	O
code	O
tool	O
developers	O
to	O
do	O
code	O
refactoring	O
and	O
fixes	O
.	O
</s>
<s>
Work-space	O
APIs	B-Application
allow	O
plugin	O
developers	O
to	O
perform	O
actions	O
specifically	O
required	O
in	O
integrated	B-Application
development	I-Application
environments	I-Application
(	O
IDEs	O
)	O
like	O
Visual	B-Application
Studio	I-Application
such	O
as	O
finding	O
references	O
of	O
a	O
variable	O
or	O
code	O
formatting	O
.	O
</s>
<s>
Compiler	B-Language
APIs	B-Application
allow	O
even	O
more	O
sophisticated	O
analysis	O
of	O
source	O
code	O
,	O
by	O
exposing	O
direct	O
calls	O
to	O
perform	O
syntax	O
tree	O
and	O
binding	O
flow	O
analysis	O
.	O
</s>
<s>
Using	O
an	O
open-source	B-Application
implementation	O
of	O
Common	O
Language	O
Infrastructure	O
(	O
CLI	O
)	O
such	O
as	O
.NET	B-Application
Core	I-Application
,	O
Roslyn	B-Application
will	O
be	O
able	O
to	O
compile	B-Language
in	O
a	O
platform-agnostic	O
manner	O
capable	O
of	O
running	O
CLI	O
code	O
in	O
Linux	B-Application
,	O
OS	B-Operating_System
X	I-Operating_System
,	O
and	O
Windows	O
.	O
</s>
