<s>
A	O
model	B-Language
transformation	I-Language
language	I-Language
in	O
systems	O
and	O
software	B-General_Concept
engineering	I-General_Concept
is	O
a	O
language	O
intended	O
specifically	O
for	O
model	B-Language
transformation	I-Language
.	O
</s>
<s>
The	O
notion	O
of	O
model	B-Language
transformation	I-Language
is	O
central	O
to	O
model-driven	B-Language
development	I-Language
.	O
</s>
<s>
A	O
model	B-Language
transformation	I-Language
,	O
which	O
is	O
essentially	O
a	O
program	O
which	O
operates	O
on	O
models	O
,	O
can	O
be	O
written	O
in	O
a	O
general-purpose	O
programming	O
language	O
,	O
such	O
as	O
Java	B-Language
.	O
</s>
<s>
However	O
,	O
special-purpose	O
model	B-Language
transformation	I-Language
languages	I-Language
can	O
offer	O
advantages	O
,	O
such	O
as	O
syntax	O
that	O
makes	O
it	O
easy	O
to	O
refer	O
to	O
model	O
elements	O
.	O
</s>
<s>
For	O
writing	O
bidirectional	O
model	B-Language
transformations	I-Language
,	O
which	O
maintain	O
consistency	O
between	O
two	O
or	O
more	O
models	O
,	O
a	O
specialist	O
bidirectional	O
model	B-Language
transformation	I-Language
language	I-Language
is	O
particularly	O
important	O
,	O
because	O
it	O
can	O
help	O
avoid	O
the	O
duplication	O
that	O
would	O
result	O
from	O
writing	O
each	O
direction	O
of	O
the	O
transformation	O
separately	O
.	O
</s>
<s>
Currently	O
,	O
most	O
model	B-Language
transformation	I-Language
languages	I-Language
are	O
being	O
developed	O
in	O
academia	O
.	O
</s>
<s>
The	O
OMG	B-Architecture
has	O
standardised	O
a	O
family	O
of	O
model	B-Language
transformation	I-Language
languages	I-Language
called	O
QVT	B-Language
,	O
but	O
the	O
field	O
is	O
still	O
immature	O
.	O
</s>
<s>
Epsilon	O
family	O
(	O
see	O
)	O
:	O
a	O
model	O
management	O
platform	O
that	O
provides	O
transformation	B-Application
languages	I-Application
for	O
model-to-model	O
,	O
model-to-text	O
,	O
update-in-place	O
,	O
migration	O
and	O
model	O
merging	O
transformations	O
.	O
</s>
<s>
F-Alloy	O
:	O
a	O
DSL	B-Language
reusing	O
part	O
of	O
the	O
Alloy	B-Application
syntax	O
and	O
allowing	O
the	O
concise	O
specification	O
of	O
efficiently	O
computable	O
model	B-Language
transformations	I-Language
.	O
</s>
<s>
JTL	O
:	O
a	O
bidirectional	O
model	B-Language
transformation	I-Language
language	I-Language
specifically	O
designed	O
to	O
support	O
non-bijective	O
transformations	O
and	O
change	O
propagation	O
(	O
see	O
)	O
.	O
</s>
<s>
MOLA	O
(	O
see	O
)	O
:	O
a	O
graphical	O
high-level	O
transformation	B-Application
language	I-Application
built	O
in	O
upon	O
Lx	O
.	O
</s>
<s>
QVT	B-Language
:	O
the	O
OMG	B-Architecture
has	O
defined	O
a	O
standard	O
for	O
expressing	O
M2M	B-Application
transformations	O
,	O
called	O
MOF/QVT	O
or	O
in	O
short	O
QVT	B-Language
.	O
</s>
