<s>
Within	O
computing	O
,	O
the	O
Rosetta	O
system-level	O
specification	B-Application
language	I-Application
is	O
a	O
design	O
language	O
for	O
complex	O
,	O
heterogeneous	O
systems	O
.	O
</s>
<s>
The	O
objective	O
of	O
the	O
meeting	O
was	O
to	O
define	O
requirements	O
for	O
a	O
next-generation	O
design	O
language	O
that	O
would	O
address	O
perceived	O
shortcomings	O
in	O
existing	O
languages	O
such	O
as	O
VHDL	B-Language
and	O
Verilog	B-Language
.	O
</s>
<s>
Specific	O
concerns	O
included	O
inability	O
to	O
represent	O
constraints	O
,	O
lack	O
of	O
a	O
formal	B-Application
semantics	I-Application
,	O
inability	O
to	O
represent	O
heterogeneous	O
systems	O
,	O
and	O
heavy	O
reliance	O
on	O
computer	B-Application
simulation	I-Application
for	O
analysis	O
.	O
</s>
<s>
The	O
first	O
approach	O
ultimately	O
resulted	O
in	O
SystemVerilog	B-Language
and	O
extensions	O
to	O
VHDL	B-Language
while	O
the	O
second	O
resulted	O
in	O
SystemC	B-Language
,	O
all	O
of	O
which	O
became	O
Institute	O
of	O
Electrical	O
and	O
Electronics	O
Engineers	O
(	O
IEEE	O
)	O
standards	O
for	O
the	O
semiconductor	O
industry	O
.	O
</s>
<s>
Rosetta	O
's	O
original	O
application	O
domain	O
was	O
system	B-Architecture
on	I-Architecture
a	I-Architecture
chip	I-Architecture
semiconductor	O
systems	O
.	O
</s>
<s>
Standardization	O
was	O
transferred	O
to	O
VHDL	B-Language
International	O
by	O
2000	O
and	O
renamed	O
Rosetta	O
(	O
after	O
the	O
Rosetta	B-Operating_System
Stone	I-Operating_System
)	O
to	O
reflect	O
the	O
heterogeneous	O
nature	O
of	O
its	O
specifications	O
.	O
</s>
<s>
Eventually	O
,	O
VHDL	B-Language
International	O
and	O
the	O
Open	O
Verilog	B-Language
Initiative	O
merged	O
to	O
form	O
Accellera	O
,	O
an	O
industry	O
sponsored	O
consortium	B-Application
for	O
electronic	O
design	O
automation	O
(	O
EDA	O
)	O
standards	O
.	O
</s>
<s>
The	O
expression	O
language	O
is	O
a	O
non-strict	B-Application
,	O
purely	O
functional	O
,	O
typed	O
language	O
in	O
the	O
spirit	O
of	O
Haskell	B-Language
.	O
</s>
<s>
Each	O
facet	O
is	O
written	O
by	O
extending	O
a	O
domain	O
that	O
provides	O
vocabulary	O
and	O
semantics	B-Application
for	O
the	O
model	O
.	O
</s>
<s>
As	O
such	O
,	O
Rosetta	O
is	O
a	O
declarative	B-Language
language	I-Language
and	O
constructs	O
cannot	O
be	O
guaranteed	O
to	O
evaluate	O
to	O
a	O
value	O
,	O
although	O
some	O
facets	O
can	O
be	O
evaluated	O
.	O
</s>
<s>
The	O
Rosetta	O
semantics	B-Application
denotes	O
each	O
facet	O
to	O
a	O
coalgebra	O
that	O
defines	O
its	O
model-of-computation	O
.	O
</s>
<s>
Because	O
Rosetta	O
is	O
reflective	B-Language
,	O
facets	O
can	O
be	O
composed	O
and	O
transformed	O
to	O
define	O
complex	O
systems	O
.	O
</s>
<s>
Units-of-semantics	O
domains	O
define	O
basic	O
units	O
of	O
specification	O
.	O
</s>
<s>
Model-of-computation	O
domains	O
extend	O
unit-of-semantics	O
domains	O
to	O
define	O
general	O
computational	O
models	O
such	O
as	O
finite_state	O
,	O
continuous_time	O
,	O
discrete_time	O
and	O
frequency	O
.	O
</s>
