<s>
Cassowary	B-Application
is	O
an	O
incremental	O
constraint	B-Application
solving	I-Application
toolkit	O
that	O
efficiently	O
solves	O
systems	O
of	O
linear	O
equalities	O
and	O
inequalities	O
.	O
</s>
<s>
Cassowary	B-Application
was	O
developed	O
by	O
Greg	O
J	O
.	O
Badros	O
,	O
Alan	O
Borning	O
and	O
Peter	O
J	O
.	O
Stuckey	O
,	O
and	O
was	O
optimized	O
for	O
user	O
interface	O
applications	O
.	O
</s>
<s>
Badros	O
used	O
Cassowary	B-Application
amongst	O
others	O
for	O
implementing	O
Constraint	O
Cascading	B-Language
Style	I-Language
Sheets	I-Language
(	O
CCSS	O
)	O
,	O
an	O
extension	O
to	O
Cascading	B-Language
Style	I-Language
Sheets	I-Language
(	O
CSS	B-Language
)	O
.	O
</s>
<s>
Cassowary	B-Application
is	O
used	O
to	O
solve	O
these	O
constraints	O
and	O
calculate	O
the	O
final	O
layout	O
.	O
</s>
<s>
The	O
original	O
distribution	O
,	O
unmaintained	O
since	O
2000	O
,	O
included	O
Smalltalk	B-Application
,	O
C++	B-Language
and	O
Java	B-Language
implementations	O
,	O
along	O
with	O
bindings	O
for	O
GNU	B-Application
Guile	I-Application
,	O
Python	B-Language
,	O
and	O
STk	O
.	O
</s>
<s>
Third-party	O
implementations	O
exist	O
for	O
JavaScript	B-Language
,	O
Dart	B-Language
,	O
Squeak	B-Operating_System
,	O
Python	B-Language
,	O
the	O
.NET	B-Application
Framework	I-Application
,	O
and	O
Rust	B-Application
.	O
</s>
<s>
Scwm	B-Device
,	O
the	O
Scheme	B-Device
Constraints	I-Device
Window	I-Device
Manager	I-Device
.	O
</s>
<s>
As	O
of	O
2011	O
,	O
Cassowary	B-Application
is	O
being	O
used	O
as	O
the	O
algorithm	O
in	O
the	O
layout	O
engine	O
for	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
(	O
Lion	O
and	O
greater	O
)	O
and	O
iOS	B-Application
(	O
6	O
and	O
greater	O
)	O
.	O
</s>
<s>
Enaml	O
's	O
layout	O
engine	O
is	O
built	O
on	O
top	O
of	O
the	O
Cassowary	B-Application
linear	O
constraint	O
optimizer	O
.	O
</s>
