<s>
xmonad	B-Device
is	O
a	O
dynamic	B-Operating_System
window	I-Operating_System
manager	I-Operating_System
(	O
tiling	B-Algorithm
)	O
for	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
,	O
noted	O
for	O
being	O
written	O
in	O
the	O
functional	B-Language
programming	I-Language
language	I-Language
Haskell	B-Language
.	O
</s>
<s>
Begun	O
in	O
March	O
2007	O
,	O
version	O
0.1	O
was	O
announced	O
in	O
April	O
2007	O
as	O
500	O
lines	O
of	O
Haskell	B-Language
.	O
</s>
<s>
xmonad	B-Device
is	O
a	O
tiling	B-Algorithm
window	B-Application
manager	I-Application
—	O
akin	O
to	O
dwm	B-Language
,	O
larswm	O
,	O
and	O
StumpWM	B-Language
.	O
</s>
<s>
It	O
arranges	O
windows	O
in	O
a	O
non-overlapping	O
pattern	O
,	O
and	O
enables	O
managing	O
windows	O
without	O
using	O
the	O
mouse	B-Device
.	O
</s>
<s>
xmonad	B-Device
is	O
packaged	B-Application
and	O
distributed	O
on	O
a	O
wide	O
range	O
of	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
,	O
such	O
as	O
a	O
large	O
number	O
of	O
Linux	B-Application
distributions	I-Application
,	O
and	O
BSD	B-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
While	O
originally	O
a	O
clone	B-General_Concept
of	O
dwm	B-Language
(	O
derivative	O
in	O
areas	O
such	O
as	O
default	O
keybindings	O
)	O
,	O
xmonad	B-Device
now	O
supports	O
features	O
not	O
available	O
to	O
dwm	B-Language
users	O
such	O
as	O
per-workspace	O
layout	O
,	O
tiling	B-Algorithm
reflection	O
,	O
state	O
preservation	O
,	O
layout	O
mirroring	O
,	O
GNOME	B-Application
support	O
and	O
per-screen	O
status	O
bars	O
;	O
it	O
can	O
be	O
customised	O
by	O
modifying	O
an	O
external	O
configuration	O
file	O
and	O
'	O
reloaded	O
 '	O
while	O
running	O
.	O
</s>
<s>
xmonad	B-Device
features	O
have	O
begun	O
to	O
influence	O
other	O
tiling	B-Algorithm
window	B-Application
managers	I-Application
:	O
dwm	B-Language
has	O
borrowed	O
"	O
urgency	O
hooks	O
"	O
from	O
xmonad	B-Device
,	O
has	O
also	O
included	O
Xinerama	B-Device
support	O
(	O
for	O
multihead	B-General_Concept
displays	I-General_Concept
)	O
with	O
release	O
4.8	O
,	O
and	O
patches	O
exist	O
to	O
reimplement	O
xmonad	B-Device
's	O
Fibonacci	O
layout	O
.	O
</s>
<s>
In	O
2007	O
the	O
man	B-Protocol
page	I-Protocol
stated	O
:	O
By	O
utilising	O
the	O
expressivity	O
of	O
a	O
modern	O
functional	B-Language
language	I-Language
with	O
a	O
rich	O
static	O
type	O
system	O
,	O
xmonad	B-Device
provides	O
a	O
complete	O
,	O
featureful	O
window	B-Application
manager	I-Application
in	O
less	O
than	O
500	O
lines	O
of	O
code	O
,	O
with	O
an	O
emphasis	O
on	O
correctness	O
and	O
robustness	O
.	O
</s>
<s>
Internal	O
properties	O
of	O
the	O
window	B-Application
manager	I-Application
are	O
checked	O
using	O
a	O
combination	O
of	O
static	O
guarantees	O
provided	O
by	O
the	O
type	O
system	O
,	O
and	O
type-based	O
automated	B-Application
testing	I-Application
.	O
</s>
<s>
Extensions	O
to	O
the	O
core	O
system	O
,	O
including	O
emulation	O
of	O
other	O
window	B-Application
managers	I-Application
,	O
and	O
unusual	O
layout	O
algorithms	O
—	O
such	O
as	O
window	O
tiling	B-Algorithm
based	O
on	O
the	O
Fibonacci	B-Algorithm
spiral	I-Algorithm
—	O
have	O
been	O
implemented	O
by	O
the	O
active	O
community	O
and	O
are	O
available	O
as	O
a	O
library	O
.	O
</s>
<s>
In	O
addition	O
to	O
obviating	O
the	O
need	O
for	O
the	O
mouse	B-Device
,	O
the	O
xmonad	B-Device
developers	O
make	O
heavy	O
use	O
of	O
semi-formal	O
methods	O
and	O
program	B-Application
derivation	I-Application
for	O
improving	O
reliability	O
and	O
enabling	O
a	O
total	O
line	O
of	O
code	O
count	O
less	O
than	O
1200	O
,	O
as	O
of	O
version	O
0.7	O
;	O
window	B-Application
manager	I-Application
properties	O
(	O
such	O
as	O
the	O
behavior	O
of	O
window	O
focus	B-Application
)	O
are	O
checked	O
through	O
use	O
of	O
QuickCheck	B-Application
.	O
</s>
<s>
This	O
emphasis	O
makes	O
xmonad	B-Device
unusual	O
in	O
a	O
number	O
of	O
ways	O
;	O
besides	O
being	O
the	O
first	O
window	B-Application
manager	I-Application
written	O
in	O
Haskell	B-Language
,	O
it	O
is	O
also	O
the	O
first	O
to	O
use	O
the	O
zipper	B-Application
data	I-Application
structure	I-Application
for	O
automatically	O
managing	O
focus	B-Application
,	O
and	O
its	O
core	O
has	O
been	O
proven	O
to	O
be	O
safe	O
with	O
respect	O
to	O
pattern	B-Language
matches	I-Language
,	O
contributing	O
further	O
to	O
reliability	O
.	O
</s>
<s>
xmonad	B-Device
is	O
a	O
tiling	B-Algorithm
window	B-Application
manager	I-Application
for	O
the	O
X	B-Operating_System
Window	I-Operating_System
system	I-Operating_System
,	O
implemented	O
,	O
configured	O
and	O
dynamically	O
extensible	O
in	O
Haskell	B-Language
.	O
</s>
<s>
This	O
demonstration	O
presents	O
the	O
case	O
that	O
software	O
dominated	O
by	O
side	O
effects	O
can	O
be	O
developed	O
with	O
the	O
precision	O
and	O
efficiency	O
we	O
expect	O
from	O
Haskell	B-Language
by	O
utilising	O
purely	O
functional	O
data	B-General_Concept
structures	I-General_Concept
,	O
an	O
expressive	O
type	O
system	O
,	O
extended	O
static	O
checking	O
and	O
property-based	O
testing	O
.	O
</s>
<s>
According	O
to	O
Alejandro	O
Serrano	O
Mena	O
,	O
there	O
are	O
two	O
ways	O
of	O
implementing	O
domain-specific	B-Language
languages	I-Language
for	O
actions	O
in	O
Haskell	B-Language
applications	B-Application
and	O
libraries	B-Library
:	O
"	O
developing	O
a	O
combinator	B-Library
library	I-Library
"	O
or	O
"	O
rolling	O
your	O
own	O
monad	O
"	O
,	O
with	O
xmonad	B-Device
being	O
a	O
successful	O
example	O
of	O
the	O
latter	O
.	O
</s>
<s>
xmonad	B-Device
was	O
regarded	O
as	O
one	O
of	O
the	O
most	O
well	O
known	O
Haskell	B-Language
projects	O
in	O
a	O
2013	O
functional	B-Language
programming	I-Language
book	O
.	O
</s>
<s>
Linux	O
Magazine	O
included	O
xmonad	B-Device
in	O
a	O
list	O
of	O
"	O
My	O
Top	O
Resources	O
of	O
2009	O
"	O
.	O
</s>
<s>
In	O
2012	O
,	O
How-To	O
Geek	O
described	O
xmonad	B-Device
as	O
having	O
good	O
,	O
but	O
complicated	O
,	O
ability	O
to	O
be	O
configured	O
,	O
and	O
it	O
was	O
included	O
in	O
a	O
2013	O
list	O
of	O
eight	O
desktop	O
environments	O
for	O
Linux	O
.	O
</s>
<s>
Lifehacker	O
wrote	O
that	O
the	O
basic	O
operations	O
of	O
xmonads	B-Device
user	O
interface	O
can	O
be	O
taught	O
using	O
a	O
small	O
set	O
of	O
instructions	O
.	O
</s>
<s>
A	O
high	O
level	O
of	O
customisation	O
and	O
speed	O
were	O
noted	O
by	O
Network	O
World	O
,	O
and	O
in	O
MakeUseOf	O
xmonad	B-Device
was	O
reviewed	O
positively	O
compared	O
to	O
Openbox	B-Language
.	O
</s>
<s>
In	O
2016	O
Ars	O
Technica	O
said	O
xmonad	B-Device
and	O
Awesome	B-Language
had	O
more	O
advanced	O
tiling	B-Algorithm
ability	O
than	O
Cinnamon	B-Language
.	O
</s>
<s>
In	O
2017	O
it	O
was	O
described	O
as	O
powerful	O
,	O
with	O
application	O
as	O
a	O
windows	B-Application
manager	I-Application
for	O
big	B-Application
data	I-Application
,	O
while	O
in	O
an	O
article	O
on	O
opensource.com	O
on	O
the	O
other	O
hand	O
,	O
dwm	B-Language
was	O
chosen	O
over	O
xmonad	B-Device
.	O
</s>
<s>
Due	O
to	O
the	O
small	O
number	O
of	O
lines	O
of	O
code	O
of	O
the	O
Xmonad	B-Device
application	O
,	O
the	O
use	O
of	O
the	O
purely	B-Application
functional	I-Application
programming	I-Application
language	O
Haskell	B-Language
,	O
and	O
recorded	O
use	O
of	O
a	O
rigorous	O
testing	O
procedure	O
it	O
is	O
sometimes	O
used	O
as	O
a	O
baseline	O
application	O
in	O
other	O
research	O
projects	O
.	O
</s>
<s>
This	O
has	O
included	O
re-implementation	O
of	O
xmonad	B-Device
using	O
the	O
Coq	B-Application
proof	I-Application
assistant	I-Application
,	O
a	O
determination	O
xmonad	B-Device
is	O
an	O
imperative	B-Application
program	I-Application
,	O
and	O
studies	O
of	O
package	B-Application
management	I-Application
relating	O
to	O
the	O
NixOS	O
linux	B-Application
distribution	I-Application
.	O
</s>
