<s>
Programming	B-Language
style	I-Language
,	O
also	O
known	O
as	O
code	B-Language
style	I-Language
,	O
is	O
a	O
set	O
of	O
rules	O
or	O
guidelines	O
used	O
when	O
writing	O
the	O
source	O
code	O
for	O
a	O
computer	B-Application
program	I-Application
.	O
</s>
<s>
It	O
is	O
often	O
claimed	O
that	O
following	O
a	O
particular	O
programming	B-Language
style	I-Language
will	O
help	O
programmers	B-Application
read	O
and	O
understand	O
source	O
code	O
conforming	O
to	O
the	O
style	O
,	O
and	O
help	O
to	O
avoid	O
introducing	O
errors	O
.	O
</s>
<s>
A	O
classic	O
work	O
on	O
the	O
subject	O
was	O
The	O
Elements	O
of	O
Programming	B-Language
Style	I-Language
,	O
written	O
in	O
the	O
1970s	O
,	O
and	O
illustrated	O
with	O
examples	O
from	O
the	O
Fortran	B-Application
and	O
PL/I	B-Language
languages	O
prevalent	O
at	O
the	O
time	O
.	O
</s>
<s>
The	O
programming	B-Language
style	I-Language
used	O
in	O
a	O
particular	O
program	O
may	O
be	O
derived	O
from	O
the	O
coding	O
conventions	O
of	O
a	O
company	O
or	O
other	O
computing	O
organization	O
,	O
as	O
well	O
as	O
the	O
preferences	O
of	O
the	O
author	O
of	O
the	O
code	O
.	O
</s>
<s>
Programming	B-Language
styles	I-Language
are	O
often	O
designed	O
for	O
a	O
specific	O
programming	O
language	O
(	O
or	O
language	O
family	O
)	O
:	O
style	O
considered	O
good	O
in	O
C	B-Language
source	O
code	O
may	O
not	O
be	O
appropriate	O
for	O
BASIC	B-Language
source	O
code	O
,	O
etc	O
.	O
</s>
<s>
However	O
,	O
there	O
are	O
several	O
elements	O
common	O
to	O
a	O
large	O
number	O
of	O
programming	B-Language
styles	I-Language
.	O
</s>
<s>
The	O
issues	O
usually	O
considered	O
as	O
part	O
of	O
programming	B-Language
style	I-Language
include	O
the	O
layout	B-Language
of	O
the	O
source	O
code	O
,	O
including	O
indentation	O
;	O
the	O
use	O
of	O
white	O
space	O
around	O
operators	O
and	O
keywords	O
;	O
the	O
capitalization	O
or	O
otherwise	O
of	O
keywords	O
and	O
variable	O
names	O
;	O
the	O
style	O
and	O
spelling	O
of	O
user-defined	O
identifiers	O
,	O
such	O
as	O
function	O
,	O
procedure	O
and	O
variable	O
names	O
;	O
and	O
the	O
use	O
and	O
style	O
of	O
comments	O
.	O
</s>
<s>
Programming	B-Language
styles	I-Language
commonly	O
deal	O
with	O
the	O
visual	O
appearance	O
of	O
source	O
code	O
,	O
with	O
the	O
goal	O
of	O
readability	O
.	O
</s>
<s>
Software	O
has	O
long	O
been	O
available	O
that	O
formats	O
source	O
code	O
automatically	O
,	O
leaving	O
coders	B-Application
to	O
concentrate	O
on	O
naming	O
,	O
logic	O
,	O
and	O
higher	O
techniques	O
.	O
</s>
<s>
Lua	B-Language
does	O
not	O
use	O
the	O
traditional	O
curly	O
braces	O
or	O
parentheses	O
;	O
rather	O
,	O
the	O
expression	O
in	O
a	O
conditional	O
statement	O
must	O
be	O
followed	O
by	O
then	O
,	O
and	O
the	O
block	O
must	O
be	O
closed	O
with	O
end	O
.	O
</s>
<s>
Indentation	O
is	O
optional	O
in	O
Lua	B-Language
.	O
</s>
<s>
and	O
,	O
or	O
,	O
and	O
not	O
function	O
as	O
logical	O
operators	O
in	O
Lua	B-Language
.	O
</s>
<s>
Python	B-Language
uses	O
indentation	O
to	O
indicate	O
control	O
structures	O
,	O
so	O
correct	O
indentation	O
is	O
required	O
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
copying	O
and	O
pasting	O
Python	B-Language
code	I-Language
can	O
lead	O
to	O
problems	O
,	O
because	O
the	O
indentation	O
level	O
of	O
the	O
pasted	O
code	O
may	O
not	O
be	O
the	O
same	O
as	O
the	O
indentation	O
level	O
of	O
the	O
current	O
line	O
.	O
</s>
<s>
Such	O
reformatting	O
can	O
be	O
tedious	O
to	O
do	O
by	O
hand	O
,	O
but	O
some	O
text	B-Application
editors	I-Application
and	O
IDEs	O
have	O
features	O
to	O
do	O
it	O
automatically	O
.	O
</s>
<s>
There	O
are	O
also	O
problems	O
when	O
Python	B-Language
code	I-Language
being	O
rendered	O
unusable	O
when	O
posted	O
on	O
a	O
forum	O
or	O
web	O
page	O
that	O
removes	O
white	O
space	O
,	O
though	O
this	O
problem	O
can	O
be	O
avoided	O
where	O
it	O
is	O
possible	O
to	O
enclose	O
code	O
in	O
white	O
space-preserving	O
tags	O
such	O
as	O
"	O
pre	O
...	O
/pre	O
"	O
(	O
for	O
HTML	B-Language
)	O
,	O
"[code]"	O
...	O
"[/code]"	O
(	O
for	O
bbcode	B-Language
)	O
,	O
etc	O
.	O
</s>
<s>
Notice	O
that	O
Python	B-Language
does	O
not	O
use	O
curly	O
braces	O
,	O
but	O
a	O
regular	O
colon	O
(	O
e.g.	O
</s>
<s>
Many	O
Python	B-Language
programmers	B-Application
tend	O
to	O
follow	O
a	O
commonly	O
agreed	O
style	O
guide	O
known	O
as	O
PEP8	O
.	O
</s>
<s>
Haskell	B-Language
similarly	O
has	O
the	O
off-side	B-Language
rule	I-Language
,	O
i.e.	O
</s>
<s>
Haskell	B-Language
is	O
a	O
declarative	O
language	O
,	O
there	O
are	O
statements	O
,	O
but	O
declarations	O
within	O
a	O
Haskell	B-Language
script	O
.	O
</s>
<s>
Haskell	B-Language
encourages	O
the	O
use	O
of	O
literate	B-Application
programming	I-Application
,	O
where	O
extended	O
text	O
explains	O
the	O
genesis	O
of	O
the	O
code	O
.	O
</s>
<s>
In	O
literate	O
Haskell	B-Language
scripts	O
(	O
named	O
with	O
the	O
lhs	O
extension	O
)	O
,	O
everything	O
is	O
a	O
comment	O
except	O
blocks	O
marked	O
as	O
code	O
.	O
</s>
<s>
The	O
program	O
can	O
be	O
written	O
in	O
LaTeX	B-Application
,	O
in	O
such	O
case	O
the	O
code	O
environment	O
marks	O
what	O
is	O
code	O
.	O
</s>
<s>
Here	O
an	O
example	O
using	O
LaTeX	B-Application
markup	O
:	O
</s>
<s>
For	O
example	O
,	O
if	O
an	O
identifier	O
with	O
a	O
long	O
name	O
is	O
added	O
to	O
a	O
tabular	O
layout	B-Language
,	O
the	O
column	O
width	O
may	O
have	O
to	O
be	O
increased	O
to	O
accommodate	O
it	O
.	O
</s>
<s>
This	O
is	O
detrimental	O
to	O
Revision	B-Architecture
control	I-Architecture
where	O
inspecting	O
differences	O
between	O
versions	O
is	O
essential	O
.	O
</s>
<s>
Brittleness	O
;	O
if	O
a	O
programmer	B-Application
does	O
not	O
neatly	O
format	O
the	O
table	O
when	O
making	O
a	O
change	O
,	O
maybe	O
legitimately	O
with	O
the	O
previous	O
point	O
in	O
mind	O
,	O
the	O
result	O
becomes	O
a	O
mess	O
that	O
deteriorates	O
with	O
further	O
such	O
changes	O
.	O
</s>
<s>
This	O
may	O
put	O
off	O
a	O
programmer	B-Application
from	O
making	O
a	O
beneficial	O
change	O
,	O
such	O
as	O
adding	O
,	O
correcting	O
or	O
improving	O
the	O
name	O
of	O
an	O
identifier	O
,	O
because	O
it	O
will	O
mess	O
up	O
the	O
formatting	O
.	O
</s>
<s>
Many	O
modern	O
code	B-Application
editors	I-Application
support	O
proportional	O
fonts	O
,	O
and	O
the	O
programmer	B-Application
may	O
prefer	O
to	O
use	O
a	O
proportional	O
font	O
for	O
readability	O
.	O
</s>
<s>
a	O
source	B-Application
code	I-Application
editor	I-Application
that	O
supports	O
elastic	O
tabstops	O
)	O
,	O
although	O
that	O
creates	O
a	O
reliance	O
on	O
such	O
tools	O
.	O
</s>
<s>
In	O
those	O
situations	O
where	O
some	O
white	O
space	O
is	O
required	O
,	O
the	O
grammars	O
of	O
most	O
free-format	B-Language
languages	I-Language
are	O
unconcerned	O
with	O
the	O
amount	O
that	O
appears	O
.	O
</s>
<s>
For	O
instance	O
,	O
compare	O
the	O
following	O
syntactically	O
equivalent	O
examples	O
of	O
C	B-Language
code	O
:	O
</s>
<s>
As	O
an	O
example	O
,	O
one	O
programmer	B-Application
prefers	O
tab	O
stops	O
of	O
four	O
and	O
has	O
their	O
toolset	O
configured	O
this	O
way	O
,	O
and	O
uses	O
these	O
to	O
format	O
their	O
code	O
.	O
</s>
<s>
Another	O
programmer	B-Application
prefers	O
tab	O
stops	O
of	O
eight	O
,	O
and	O
their	O
toolset	O
is	O
configured	O
this	O
way	O
.	O
</s>
