<s>
Noweb	B-Application
,	O
stylised	O
in	O
lowercase	O
as	O
noweb	B-Application
,	O
is	O
a	O
literate	B-Application
programming	I-Application
tool	O
,	O
created	O
in	O
1989	O
–	O
1999	O
by	O
Norman	O
Ramsey	O
,	O
and	O
designed	O
to	O
be	O
simple	O
,	O
easily	O
extensible	O
and	O
language	O
independent	O
.	O
</s>
<s>
As	O
in	O
WEB	O
and	O
CWEB	B-Application
,	O
the	O
main	O
components	O
of	O
Noweb	B-Application
are	O
two	O
programs	O
:	O
"	O
notangle	O
"	O
,	O
which	O
extracts	O
'	O
machine	O
 '	O
source	O
code	O
from	O
the	O
source	O
texts	O
,	O
and	O
"	O
noweave	O
"	O
,	O
which	O
produces	O
nicely-formatted	O
printable	O
documentation	O
.	O
</s>
<s>
Noweb	B-Application
supports	O
TeX	B-Application
,	O
LaTeX	B-Application
,	O
HTML	B-Language
,	O
and	O
troff	B-Language
back	O
ends	O
and	O
works	O
with	O
any	O
programming	O
language	O
.	O
</s>
<s>
Besides	O
simplicity	O
this	O
is	O
the	O
main	O
advantage	O
over	O
WEB	O
,	O
which	O
needs	O
different	O
versions	O
to	O
support	O
programming	O
languages	O
other	O
than	O
Pascal	B-Application
.	O
</s>
<s>
(	O
Thus	O
the	O
necessity	O
of	O
CWEB	B-Application
,	O
which	O
supports	O
C	B-Language
and	O
similar	O
languages	O
.	O
)	O
</s>
<s>
A	O
Noweb	B-Application
input	O
text	O
contains	O
program	O
source	O
code	O
interleaved	O
with	O
documentation	O
.	O
</s>
<s>
Documentation	O
chunks	O
normally	O
contain	O
LaTeX	B-Application
,	O
but	O
Noweb	B-Application
is	O
also	O
used	O
with	O
HTML	B-Language
,	O
plain	B-Application
TeX	I-Application
,	O
and	O
with	O
troff	B-Language
.	O
</s>
<s>
Code	O
chunks	O
are	O
n't	O
treated	O
specially	O
by	O
Noweb	B-Application
's	O
tools	O
—	O
they	O
may	O
be	O
placed	O
in	O
any	O
order	O
and	O
,	O
when	O
needed	O
,	O
they	O
are	O
just	O
concatenated	O
.	O
</s>
<s>
Assuming	O
that	O
the	O
above	O
code	O
is	O
placed	O
in	O
a	O
file	O
named	O
'	O
hello.nw	O
'	O
,	O
the	O
command	O
to	O
extract	O
the	O
human-readable	O
document	O
in	O
HTML	B-Language
format	O
is	O
:	O
</s>
<s>
...	O
and	O
in	O
LaTeX	B-Application
format	O
:	O
</s>
<s>
Noweb	B-Application
defines	O
a	O
specific	O
file	O
format	O
and	O
a	O
file	O
is	O
likely	O
to	O
interleave	O
three	O
different	O
formats	O
(	O
Noweb	B-Application
,	O
LaTeX	B-Application
and	O
the	O
language	O
used	O
for	O
the	O
software	O
)	O
.	O
</s>
<s>
This	O
is	O
not	O
recognised	O
by	O
other	O
software	O
development	O
tools	O
and	O
consequently	O
using	O
Noweb	B-Application
excludes	O
the	O
use	O
of	O
UML	B-Language
or	O
code	O
documentation	O
tools	O
.	O
</s>
