<s>
parboiled	B-Language
is	O
an	O
open-source	O
Java	B-Language
library	O
released	O
under	O
an	O
Apache	B-Application
License	I-Application
.	O
</s>
<s>
It	O
provides	O
support	O
for	O
defining	O
PEG	O
parsers	O
directly	O
in	O
Java	B-Language
source	I-Language
code	I-Language
.	O
</s>
<s>
parboiled	B-Language
is	O
commonly	O
used	O
as	O
an	O
alternative	O
for	O
regular	B-Language
expressions	I-Language
or	O
parser	B-Language
generators	I-Language
(	O
like	O
ANTLR	B-Application
or	O
JavaCC	B-Language
)	O
,	O
especially	O
for	O
smaller	O
and	O
medium-size	O
applications	O
.	O
</s>
<s>
Apart	O
from	O
providing	O
the	O
constructs	O
for	O
grammar	O
definition	O
parboiled	B-Language
implements	O
a	O
complete	O
recursive	B-Application
descent	I-Application
parser	I-Application
with	O
support	O
for	O
abstract	B-Data_Structure
syntax	I-Data_Structure
tree	I-Data_Structure
construction	O
,	O
parse	O
error	O
reporting	O
and	O
parse	O
error	O
recovery	O
.	O
</s>
<s>
Since	O
parsing	O
with	O
parboiled	B-Language
does	O
not	O
require	O
a	O
separate	O
lexing	B-Application
phase	O
and	O
there	O
is	O
no	O
special	O
syntax	O
to	O
learn	O
for	O
grammar	O
definition	O
parboiled	B-Language
makes	O
it	O
comparatively	O
easy	O
to	O
build	O
custom	O
parsers	O
quickly	O
.	O
</s>
<s>
With	O
parboiled	B-Language
this	O
rule	O
description	O
can	O
be	O
translated	O
directly	O
into	O
the	O
following	O
Java	B-Language
code	I-Language
:	O
</s>
