<s>
Treelang	B-Language
is	O
a	O
"	O
toy	O
"	O
programming	O
language	O
distributed	O
with	O
the	O
GNU	B-Application
Compiler	I-Application
Collection	I-Application
(	O
GCC	B-Application
)	O
to	O
demonstrate	O
the	O
features	O
of	O
its	O
code-generation	B-Application
backend	B-Architecture
.	O
</s>
<s>
During	O
the	O
GCC	B-Application
4.3	O
release	O
cycle	O
,	O
a	O
patch	O
was	O
committed	O
to	O
remove	O
the	O
language	O
,	O
because	O
of	O
high	O
maintenance	O
costs	O
outweighing	O
its	O
benefits	O
and	O
also	O
because	O
it	O
was	O
no	O
longer	O
considered	O
a	O
good	O
front-end	B-Architecture
example	O
by	O
GCC	B-Application
developers	O
.	O
</s>
<s>
Treelang	B-Language
is	O
loosely	O
based	O
on	O
the	O
C	B-Language
programming	I-Language
language	I-Language
,	O
but	O
omits	O
complex	O
features	O
such	O
as	O
pointers	O
,	O
arrays	B-Data_Structure
,	O
and	O
records	O
.	O
</s>
<s>
From	O
the	O
documentation	O
distributed	O
with	O
GCC	B-Application
:	O
</s>
<s>
Treelang	B-Language
is	O
a	O
sample	O
language	O
,	O
useful	O
only	O
to	O
help	O
people	O
understand	O
how	O
to	O
implement	O
a	O
new	O
language	O
front	B-Architecture
end	I-Architecture
to	O
GCC	B-Application
.	O
</s>
<s>
The	O
following	O
example	O
is	O
from	O
the	O
Treelang	B-Language
documentation	O
,	O
modified	O
by	O
adding	O
the	O
main	O
function	O
,	O
and	O
is	O
included	O
to	O
give	O
an	O
impression	O
of	O
the	O
Treelang	B-Language
syntax	O
and	O
semantics	O
:	O
</s>
<s>
Note	O
that	O
C-style	O
comments	O
(	O
with	O
the	O
/	O
*	O
*	O
/	O
syntax	O
)	O
are	O
not	O
legal	O
in	O
Treelang	B-Language
.	O
</s>
<s>
As	O
a	O
simple	O
,	O
C-like	O
language	O
,	O
Treelang	B-Language
is	O
interoperable	O
with	O
C	B-Language
and	O
C++	B-Language
with	O
some	O
minor	O
datatype	O
caveats	O
.	O
</s>
<s>
The	O
designated	O
filename	O
extension	O
for	O
Treelang	B-Language
source	O
code	O
files	O
is	O
.tree	O
.	O
</s>
<s>
Treelang	B-Language
source	O
code	O
can	O
be	O
compiled	O
by	O
invoking	O
gcc	B-Application
normally	O
or	O
as	O
gtreelang	O
.	O
</s>
<s>
Both	O
invocations	O
run	O
the	O
Treelang	B-Language
frontend	B-Architecture
(	O
internally	O
labelled	O
tree1	O
)	O
and	O
produce	O
machine	O
code	O
as	O
output	O
.	O
</s>
<s>
Treelang	B-Language
can	O
also	O
issue	O
some	O
warning	O
messages	O
.	O
</s>
