<s>
Doxygen	B-Language
(	O
)	O
is	O
a	O
documentation	B-Protocol
generator	I-Protocol
and	O
static	O
analysis	O
tool	O
for	O
software	O
source	O
trees	O
.	O
</s>
<s>
When	O
used	O
as	O
a	O
documentation	B-Protocol
generator	I-Protocol
,	O
Doxygen	B-Language
extracts	O
information	O
from	O
specially-formatted	O
comments	O
within	O
the	O
code	O
.	O
</s>
<s>
When	O
used	O
for	O
analysis	O
,	O
Doxygen	B-Language
uses	O
its	O
parse	O
tree	O
to	O
generate	O
diagrams	O
and	O
charts	O
of	O
the	O
code	O
structure	O
.	O
</s>
<s>
Doxygen	B-Language
can	O
cross	O
reference	O
documentation	O
and	O
code	O
,	O
so	O
that	O
the	O
reader	O
of	O
a	O
document	O
can	O
easily	O
refer	O
to	O
the	O
actual	O
code	O
.	O
</s>
<s>
Doxygen	B-Language
is	O
free	B-Application
software	I-Application
,	O
released	O
under	O
the	O
terms	O
of	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
version2	O
(	O
GPLv2	B-License
)	O
.	O
</s>
<s>
Like	O
Javadoc	B-Language
,	O
Doxygen	B-Language
extracts	O
documentation	O
from	O
source	O
file	O
comments	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
Javadoc	B-Language
syntax	O
,	O
Doxygen	B-Language
supports	O
the	O
documentation	O
tags	O
used	O
in	O
the	O
Qt	B-Language
toolkit	I-Language
and	O
can	O
generate	O
output	O
in	O
HyperText	B-Language
Markup	I-Language
Language	I-Language
(	O
HTML	B-Language
)	O
as	O
well	O
as	O
in	O
Microsoft	B-Protocol
Compiled	I-Protocol
HTML	I-Protocol
Help	I-Protocol
(	O
CHM	O
)	O
,	O
Rich	O
Text	O
Format	O
(	O
RTF	O
)	O
,	O
Portable	B-Application
Document	I-Application
Format	I-Application
(	O
PDF	B-Application
)	O
,	O
LaTeX	B-Application
,	O
PostScript	B-Language
or	O
man	B-Protocol
pages	I-Protocol
.	O
</s>
<s>
Programming	O
languages	O
supported	O
by	O
Doxygen	B-Language
include	O
C	B-Language
,	O
C++	B-Language
,	O
C#	B-Application
,	O
D	B-Application
,	O
Fortran	B-Application
,	O
IDL	B-General_Concept
,	O
Java	B-Language
,	O
Objective-C	B-Language
,	O
Perl	B-Language
,	O
PHP	B-Application
,	O
Python	B-Language
,	O
and	O
VHDL	B-Language
.	O
</s>
<s>
Doxygen	B-Language
runs	O
on	O
most	O
Unix-like	B-Operating_System
systems	I-Operating_System
,	O
macOS	B-Application
,	O
and	O
Windows	B-Application
.	O
</s>
<s>
The	O
first	O
version	O
of	O
Doxygen	B-Language
borrowed	O
code	O
from	O
an	O
early	O
version	O
of	O
DOC++	O
,	O
developed	O
by	O
Roland	O
Wunderling	O
and	O
Malte	O
Zöckler	O
at	O
Zuse	O
Institute	O
Berlin	O
.	O
</s>
<s>
Later	O
,	O
the	O
Doxygen	B-Language
code	O
was	O
rewritten	O
by	O
Dimitri	B-Language
van	I-Language
Heesch	I-Language
.	O
</s>
<s>
Doxygen	B-Language
has	O
built-in	O
support	O
to	O
generate	O
inheritance	O
diagrams	O
for	O
C++	B-Language
classes	O
.	O
</s>
<s>
For	O
more	O
advanced	O
diagrams	O
and	O
graphs	O
,	O
Doxygen	B-Language
can	O
use	O
the	O
"	O
dot	O
"	O
tool	O
from	O
Graphviz	B-Language
.	O
</s>
<s>
Many	O
programmers	O
avoid	O
using	O
C-style	O
comments	O
and	O
instead	O
use	O
C++	B-Language
style	O
single	O
line	O
comments	O
.	O
</s>
<s>
Doxygen	B-Language
accepts	O
comments	O
with	O
additional	O
slash	O
as	O
Doxygen	B-Language
comments	O
.	O
</s>
<s>
The	O
following	O
illustrates	O
how	O
a	O
C++	B-Language
source	O
file	O
can	O
be	O
documented	O
.	O
</s>
<s>
For	O
instance	O
,	O
add	O
equations	O
using	O
LaTeX	B-Application
commands	O
:	O
</s>
<s>
The	O
Doxygen	B-Language
sources	O
are	O
currently	O
hosted	O
at	O
GitHub	B-Application
,	O
where	O
the	O
main	O
developer	O
,	O
Dimitri	B-Language
van	I-Language
Heesch	I-Language
,	O
contributes	O
under	O
the	O
user	O
name	O
"	O
doxygen	B-Language
"	O
.	O
</s>
<s>
Doxygen	B-Language
is	O
written	O
in	O
C++	B-Language
,	O
and	O
consists	O
of	O
around	O
300,000	O
source	O
lines	O
of	O
code	O
.	O
</s>
<s>
For	O
lexical	B-Application
analysis	I-Application
,	O
the	O
standard	O
tool	O
Lex	B-General_Concept
(	O
or	O
its	O
replacement	O
Flex	O
)	O
is	O
run	O
via	O
approximately	O
35,000	O
lines	O
of	O
lex	B-General_Concept
script	O
.	O
</s>
<s>
The	O
parsing	O
tool	O
Yacc	B-Application
(	O
or	O
its	O
replacement	O
Bison	O
)	O
is	O
also	O
used	O
,	O
but	O
only	O
for	O
minor	O
tasks	O
;	O
the	O
bulk	O
of	O
language	O
parsing	O
is	O
done	O
by	O
native	O
C++	B-Language
code	I-Language
.	O
</s>
<s>
The	O
build	O
process	O
is	O
based	O
on	O
CMake	B-Language
and	O
also	O
involves	O
some	O
Python	B-Language
scripts	I-Language
.	O
</s>
