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Title: 3.0 document tab interpretation change
Type: Stage:
Components: Documentation Versions: Python 3.0, Python 3.1
Status: closed Resolution: fixed
Dependencies: Superseder:
Assigned To: georg.brandl Nosy List: georg.brandl, terry.reedy
Priority: normal Keywords:

Created on 2008-12-08 23:05 by terry.reedy, last changed 2022-04-11 14:56 by admin. This issue is now closed.

Messages (2)
msg77360 - (view) Author: Terry J. Reedy (terry.reedy) * (Python committer) Date: 2008-12-08 23:05
In 2.6, Ref Manual / Lexical Analysis / Indentation says

"First, tabs are replaced (from left to right) by one to eight spaces
such that the total number of characters up to and including the
replacement is a multiple of eight (this is intended to be the same rule
as used by Unix). The total number of spaces preceding the first
non-blank character then determines the line’s indentation. "

and Using Python / Command line / Misc options says

    Issue a warning when a source file mixes tabs and spaces for
indentation in a way that makes it depend on the worth of a tab
expressed in spaces. Issue an error when the option is given twice (-tt)."

Inyeol Lee, on c.l.p., in response to a report of a TabError, says "-tt
option in python 2.x is now default in python 3.0.
Apparently it got slipped from any documentation, including what's

In 3.0 docs, the -t option *was* removed from Using Python, but the
Indentation sentences quoted above remain unchanged, though obsolete.  I
would guess that they should be replaced by something like

"When a source file mixes tabs and spaces for indentation in a way that
makes it depend on the worth of a tab expressed in spaces, a TabError is

Perhaps What's New should get a sentence too.  "The former -tt startup
option to raise TabError on ambiguous mixtures of tabs and spaces for
indentation has been removed as an option and is now the standard behavior."
msg77852 - (view) Author: Georg Brandl (georg.brandl) * (Python committer) Date: 2008-12-15 08:50
Thanks, fixed in r67786.
Date User Action Args
2022-04-11 14:56:42adminsetgithub: 48853
2008-12-15 08:50:01georg.brandlsetstatus: open -> closed
resolution: fixed
messages: + msg77852
2008-12-08 23:05:50terry.reedycreate