Why indentation is use to denote block of code?

Mon Sep 14 03:50:46 EDT 2009

On Sep 13, 2009, at 5:38 PM, AggieDan04 wrote:
> On Sep 13, 6:27 pm, Steven D'Aprano wrote:
>> On 2009年9月13日 15:15:40 -0700, Chris Rebert wrote:
>>> In fact it's pretty much impossible to automatically indent Python 
>>> code
>>> that has had its indentation removed; it's impossible to know for 
>>> sure
>>> where the dedents should occur.
>>>> Just like most other syntactic elements -- if you remove all the 
>> return
>> statements from Python code, or dot operators, it's impossible to
>> automatically add them back in.
>>>> The only difference is that some (badly written?) applications mangle
>> leading whitespace, but very few feel free to remove other text on 
>> a whim.
>>>> I don't recall actually using a mail client or newsreader that 
>> removes
>> leading whitespace when posting, but I've occasionally seen posts 
>> from
>> others with all indentation removed, so presumably such badly-behaved
>> applications do exist.
>> I haven't seen it in a mail client, but it's very common in internet
> forums.

If you regularly deal with some sort of transport that messes with 
your leading whitespace, you may find Tools/scripts/pindent.py in the 
Python source distribution useful; it adds comments that act as block 
closers to your code, and can then use those comments to restore the 
correct indentation to a mangled version. (Most forums offer some 
sort of whitespace-preserving [code] tag, though; and pindent is 
relatively old, and apparently not well maintained (no support for 
"with" blocks)).
-Miles