peps/pep-0666.txt at main · python/peps

Cannot retrieve contributors at this time

96 lines (78 sloc) 3.92 KB

	PEP: 666
	Title: Reject Foolish Indentation
	Author: Laura Creighton <lac@strakt.com>
	Status: Rejected
	Type: Standards Track
	Content-Type: text/x-rst
	Created: 03-Dec-2001
	Python-Version: 2.2
	Post-History: 05-Dec-2001


	Abstract
	========

	Everybody agrees that mixing tabs and spaces is a bad idea. Some
	people want more than this. I propose that we let people define
	whatever Python behaviour they want, so it will only run the way
	they like it, and will not run the way they don't like it. We
	will do this with a command line switch. Programs that aren't
	formatted the way the programmer wants things will raise
	``IndentationError``.

	- ``python -TNone`` will refuse to run when there are any tabs.
	- ``python -Tn`` will refuse to run when tabs are not exactly ``n`` spaces
	- ``python -TOnly`` will refuse to run when blocks are indented by anything
	other than tabs

	People who mix tabs and spaces, naturally, will find that their
	programs do not run. Alas, we haven't found a way to give them an
	electric shock as from a cattle prod remotely. (Though if somebody
	finds out a way to do this, I will be pleased to add this option to
	the PEP.)


	Rationale
	=========

	Python-list@python.org (a.k.a. comp.lang.python) is periodically
	awash with discussions about tabs and spaces. This is inevitable,
	given that indentation is syntactically significant in Python.
	This has never solved anything, and just makes various people
	frustrated and angry. Eventually they start saying rude things to
	each other which is sad for all of us. And it is also sad that
	they are wasting their valuable time which they could spend
	creating something with Python. Moreover, for the Python community
	as a whole, from a public relations point of view, this is quite
	unfortunate. The people who aren't posting about tabs and spaces,
	are, (unsurprisingly) invisible, while the people who are posting
	make the rest of us look somewhat foolish.

	The problem is that there is no polite way to say 'Stop wasting
	your valuable time and mine.' People who are already in the middle
	of a flame war are not well disposed to believe that you are acting
	out of compassion for them, and quite rightly insist that their own
	time is their own to do with as they please. They are stuck like
	flies in treacle in this wretched argument, and it is self-evident
	that they cannot disengage or they would have already done so.

	But today I had to spend time cleaning my keyboard because the 'n'
	key is sticking. So, in addition to feeling compassion for these
	people, I am pretty annoyed. I figure if I make this PEP, we can
	then ask Guido to quickly reject it, and then when this argument
	next starts up again, we can say 'Guido isn't changing things to
	suit the tab-haters or the only-tabbers, so this conversation is a
	waste of time.' Then everybody can quietly believe that a) they
	are correct and b) other people are fools and c) they are
	undeniably fortunate to not have to share a lab with idiots, (which
	is something the arguers could do _now_, but apparently have
	forgotten).

	And python-list can go back to worrying if it is too smug, rather
	than whether it is too hostile for newcomers. Possibly somebody
	could get around to explaining to me what is the difference between
	``__getattr__`` and ``__getattribute__`` in non-Classic classes in 2.2, a
	question I have foolishly posted in the middle of the current tab
	thread. I would like to know the answer to that question [1]_.

	This proposal, if accepted, will probably mean a heck of a lot of
	work for somebody. But since I don't want it accepted, I don't
	care.


	References
	==========

	.. [1] Tim Peters already has (private correspondence). My early 2.2
	didn't have a ``__getattribute__``, and ``__getattr__`` was
	implemented like ``__getattribute__`` now is. This has been
	fixed. The important conclusion is that my Decorator Pattern
	is safe and all is right with the world.


	Copyright
	=========

	This document has been placed in the public domain.