<s>
Reo	O
is	O
a	O
domain-specific	B-Language
language	I-Language
for	O
programming	O
and	O
analyzing	O
coordination	O
protocols	O
that	O
compose	O
individual	O
processes	O
into	O
full	O
systems	O
,	O
broadly	O
construed	O
.	O
</s>
<s>
Examples	O
of	O
classes	O
of	O
systems	O
that	O
can	O
be	O
composed	O
with	O
Reo	O
include	O
component-based	B-Architecture
systems	O
,	O
service-oriented	O
systems	O
,	O
multithreading	B-Operating_System
systems	O
,	O
biological	O
systems	O
,	O
and	O
cryptographic	O
protocols	O
.	O
</s>
<s>
Such	O
a	O
graph	O
represents	O
the	O
data-flow	B-Application
among	O
the	O
processes	O
in	O
the	O
system	O
.	O
</s>
<s>
Reo	O
has	O
formal	B-Application
semantics	I-Application
,	O
which	O
stand	O
at	O
the	O
basis	O
of	O
its	O
various	O
formal	O
verification	O
techniques	O
and	O
compilation	O
tools	O
.	O
</s>
<s>
In	O
Reo	O
,	O
a	O
concurrent	O
system	O
consists	O
of	O
a	O
set	O
of	O
components	O
which	O
are	O
glued	O
together	O
by	O
a	O
circuit	O
that	O
enables	O
flow	B-Application
of	I-Application
data	I-Application
between	O
components	O
.	O
</s>
<s>
Endogenous	O
models	O
and	O
languages	O
,	O
such	O
as	O
Linda	B-Language
,	O
provide	O
primitives	O
that	O
must	O
be	O
incorporated	O
within	O
a	O
computation	O
for	O
its	O
coordination	O
.	O
</s>
<s>
However	O
,	O
they	O
generally	O
lead	O
to	O
an	O
intermixing	O
of	O
coordination	O
primitives	O
with	O
computation	O
code	O
,	O
which	O
entangles	O
the	O
semantics	B-Application
of	O
computation	O
with	O
coordination	O
protocols	O
.	O
</s>
<s>
The	O
semantics	B-Application
of	O
a	O
Reo	O
circuit	O
is	O
a	O
formal	O
description	O
of	O
its	O
behavior	O
.	O
</s>
<s>
Various	O
semantics	B-Application
for	O
Reo	O
exist	O
.	O
</s>
<s>
Historically	O
the	O
first	O
semantics	B-Application
of	O
Reo	O
was	O
based	O
on	O
the	O
coalgebraic	O
notion	O
of	O
streams	O
(	O
i.e.	O
,	O
infinite	O
sequences	O
)	O
.	O
</s>
<s>
This	O
semantics	B-Application
is	O
based	O
on	O
the	O
concept	O
of	O
a	O
timed	O
data	O
stream	O
,	O
which	O
is	O
a	O
pair	O
consisting	O
of	O
a	O
stream	O
of	O
data	O
items	O
and	O
a	O
stream	O
of	O
monotonically	O
increasing	O
time	O
stamps	O
(	O
real	O
numbers	O
)	O
.	O
</s>
<s>
Later	O
,	O
an	O
automaton-based	O
semantics	B-Application
was	O
developed	O
,	O
which	O
is	O
called	O
constraint	B-Application
automata	I-Application
.	O
</s>
<s>
A	O
constraint	B-Application
automaton	I-Application
is	O
a	O
labeled	O
transition	O
system	O
,	O
where	O
transition	O
labels	O
consist	O
of	O
a	O
synchronization	O
constraint	O
and	O
a	O
data	O
constraint	O
.	O
</s>
<s>
One	O
limitation	O
of	O
constraint	B-Application
automata	I-Application
(	O
and	O
timed	O
data	O
streams	O
)	O
is	O
that	O
they	O
cannot	O
directly	O
model	O
context-sensitive	O
behavior	O
,	O
where	O
the	O
behavior	O
of	O
a	O
channel	O
depends	O
on	O
the	O
(	O
un	O
)	O
availability	O
of	O
a	O
pending	O
I/O	O
operation	O
.	O
</s>
<s>
For	O
example	O
,	O
using	O
constraint	B-Application
automata	I-Application
,	O
it	O
is	O
impossible	O
to	O
directly	O
model	O
the	O
behavior	O
of	O
a	O
LossySync	O
,	O
which	O
should	O
lose	O
data	O
only	O
if	O
its	O
output	O
node	O
has	O
no	O
pending	O
get-request	O
.	O
</s>
<s>
To	O
solve	O
this	O
problem	O
,	O
another	O
semantics	B-Application
of	O
Reo	O
has	O
been	O
developed	O
,	O
called	O
connector	O
coloring	O
.	O
</s>
<s>
Other	O
semantics	B-Application
for	O
Reo	O
make	O
it	O
possible	O
to	O
model	O
timed	O
or	O
probabilistic	O
behavior	O
.	O
</s>
<s>
The	O
(	O
ECT	O
)	O
are	O
a	O
set	O
of	O
plug-ins	O
for	O
Eclipse	B-Application
that	O
constitute	O
an	O
integrated	B-Application
development	I-Application
environment	I-Application
(	O
IDE	O
)	O
for	O
Reo	O
.	O
</s>
<s>
The	O
ECT	O
consists	O
of	O
a	O
graphical	O
editor	O
for	O
drawing	O
circuits	O
and	O
an	O
animation	O
engine	O
for	O
animating	O
data-flow	B-Application
through	O
circuits	O
.	O
</s>
<s>
For	O
code	O
generation	O
,	O
the	O
ECT	O
contains	O
a	O
Reo-to-Java	O
compiler	O
,	O
which	O
generates	O
code	O
for	O
circuits	O
based	O
on	O
their	O
constraint	B-Application
automaton	I-Application
semantics	B-Application
.	O
</s>
<s>
In	O
particular	O
,	O
on	O
input	O
of	O
a	O
Reo	O
circuit	O
,	O
it	O
produces	O
a	O
Java	O
class	O
,	O
which	O
simulates	O
the	O
constraint	B-Application
automaton	I-Application
that	O
models	O
the	O
circuit	O
.	O
</s>
<s>
For	O
verification	O
,	O
the	O
ECT	O
contains	O
a	O
tool	O
that	O
translates	O
Reo	O
circuits	O
to	O
process	O
definitions	O
in	O
mCRL2	B-Application
.	O
</s>
<s>
Users	O
can	O
subsequently	O
use	O
mCRL2	B-Application
for	O
model	O
checking	O
against	O
mu-calculus	B-Application
property	O
specifications	O
.	O
</s>
