indentation

J. Clifford Dyer jcd at sdf.lonestar.org
Tue Oct 21 00:55:46 CEST 2008


On Mon, 2008-10-20 at 13:29 +0000, Steven D'Aprano wrote:
> On Mon, 20 Oct 2008 11:01:19 +0200, Bruno Desthuilliers wrote:
> 
> > Steven D'Aprano a écrit :
> >> On Sun, 19 Oct 2008 19:03:29 +0200, Bruno Desthuilliers wrote:
> >> 
> >>> Steven D'Aprano a écrit :
> >>>
> >>> (snip)
> >>>
> >>>> You can use tabs, or spaces. If you use spaces, you can choose 4
> >>>> spaces, or 8, or any number,
> >>> By all means, make it 4 spaces - that's the standard.
> >> 
> >> It's *a* standard. I believe it is the standard for the Python standard
> >> library, but there are other standards.
> > 
> > I can't remember having seen any other "standard" so far.
> 
> 
> How about PEP 8? It's not even hidden deep in the bowels of the PEP -- 
> it's almost at the top.
> http://www.python.org/dev/peps/pep-0008/
> 
> "For really old code that you don't want to mess up, you can continue to 
> use 8-space tabs."
> 

Fair, but limited to old code, so doesn't apply to instructions for new
code.

> 
> Then there's string.expandtabs():
> 
> expandtabs(...)
>     S.expandtabs([tabsize]) -> string
> 
>     Return a copy of S where all tab characters are expanded using spaces.
>     If tabsize is not given, a tab size of 8 characters is assumed.
> 

The default for a tab does not imply anything about how python code
should be indented.

> 
> Here's Jamie Zawinski:
> http://www.jwz.org/doc/tabs-vs-spaces.html
> 
> "On defaultly-configured Unix systems, and on ancient dumb terminals and 
> teletypes, the tradition has been for the TAB character to mean ``move to 
> the right until the current column is a multiple of 8.'' (As it happens, 
> this is how Netscape interprets TAB inside <PRE> as well.) This is also 
> the default in the two most popular Unix editors, Emacs and vi."
> 

Again, refers to the interpretation of a tab, rather than indentation
conventions.

> 
> This page is a little old (2002), but it states that the standards for 
> OpenBSD and Linux (presumably the kernels) are 8 space indents:
> 
> http://xarg.net/writing/tabs
> 

Not python.  I think when Bruno says it's *the* standard, we can assume
he means "for python."

> Here's a style guide that recommends 2, 3 or 4 space indents:
> 
> http://www.cs.bris.ac.uk/Teaching/Resources/COMS12100/style/
> 

Again, it's for java and C, not python.

> 
> And of course, whenever there's a difference of opinion, we can turn to 
> the ultimate source of all knowledge: Googlefight!  *wink*
> 
> http://www.googlefight.com/index.php?lang=en_GB&word1=tab+8
> +spaces&word2=tab+4+spaces

> Nearly 50 million hits for "tab 8 spaces" versus a piddly 762 thousand 
> hits for "tab 4 spaces".
> 
> 

And I still don't care how many spaces are in a tab. ;D

Cheers,
Cliff






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