space/tab conversion utility?

[Grant Edwards]

Is there any utility to convert Python sources from space-based
block indentation to tab-based?

You can use "expand" convert from tabs->spaces, but "unexpand"
isn't bright enough to do the reverse.

--
Grant Edwards grante Yow! By MEER biz doo
at SCHOIN...
visi.com

[David Eppstein]

In article <41************ ***********@new sreader.visi.co m>,
Grant Edwards <gr****@visi.co m> wrote:

Is there any utility to convert Python sources from space-based
block indentation to tab-based?

Why would you want to?

--
David Eppstein
Computer Science Dept., Univ. of California, Irvine
http://www.ics.uci.edu/~eppstein/

[Brian van den Broek]

Grant Edwards said unto the world upon 28/07/2004 17:49:

Is there any utility to convert Python sources from space-based
block indentation to tab-based?

You can use "expand" convert from tabs->spaces, but "unexpand"
isn't bright enough to do the reverse.

Hi,

<http://aspn.activestat e.com/ASPN/Cookbook/Python/Recipe/65226>

There are a couple of other tab/space recipes on the site, too.

Best,

Brian vdB

[Grant Edwards]

On 2004-07-28, David Eppstein <ep******@ics.u ci.edu> wrote:

In article <41************ ***********@new sreader.visi.co m>,
Grant Edwards <gr****@visi.co m> wrote:

Is there any utility to convert Python sources from space-based
block indentation to tab-based?

Why would you want to?

So that I can submit patches to a Python application whos
devloper uses tabs. My Python editor uses spaces.

--
Grant Edwards grante Yow! So this is what it
at feels like to be potato
visi.com salad

[Grant Edwards]

On 2004-07-28, Brian van den Broek <bv****@po-box.mcgill.ca> wrote:

Grant Edwards said unto the world upon 28/07/2004 17:49:

Is there any utility to convert Python sources from space-based
block indentation to tab-based?

You can use "expand" convert from tabs->spaces, but "unexpand"
isn't bright enough to do the reverse.

Hi,

<http://aspn.activestat e.com/ASPN/Cookbook/Python/Recipe/65226>

I don't see how that's useful.
There are a couple of other tab/space recipes on the site, too.

"unexpand" will do dumb conversion, but what's required is
something that understands Python block syntax. Something
similar to C's "indent" program.

--
Grant Edwards grante Yow! Did YOU find a
at DIGITAL WATCH in YOUR box
visi.com of VELVEETA?

[Brian van den Broek]

Grant Edwards said unto the world upon 28/07/2004 18:12:

On 2004-07-28, Brian van den Broek <bv****@po-box.mcgill.ca> wrote:

Grant Edwards said unto the world upon 28/07/2004 17:49:

Is there any utility to convert Python sources from space-based
block indentation to tab-based?

You can use "expand" convert from tabs->spaces, but "unexpand"
isn't bright enough to do the reverse.

Hi,

<http://aspn.activestat e.com/ASPN/Cookbook/Python/Recipe/65226>

I don't see how that's useful.

There are a couple of other tab/space recipes on the site, too.

"unexpand" will do dumb conversion, but what's required is
something that understands Python block syntax. Something
similar to C's "indent" program.

Hi,

OK, sorry. I'm still pretty new to Python and programming in general. But
I would have thought that the recipe I pointed to could be used as the
basis of a script that would uniformly replace all leading tabs with a set
number of spaces, thus preserving relative indents. (On the assumption
that the code being transformed is all tabs.)

But getting your response made me read the recipe more carefully, and now
I think I see why you doubt its usefulness for your task.

Still, the approach of replacing only leading tabs seems to me like it
would work. I did up a script and from my testing it appears to preserve
block structure. But I hesitate to post code; one gaff a day is enough ;-)

If there's a subtlety that is blowing past me in my newbieness,
enlightenment would be appreciated. On the other hand, if you'd like to
see the code, I'd be happy to share.

Anyway, sorry if I wasted your time.

Best,

Brian vdB

[Grant Edwards]

In article <ma************ *************** **********@pyth on.org>, Brian van den Broek wrote:

"unexpand" will do dumb conversion, but what's required is
something that understands Python block syntax. Something
similar to C's "indent" program.
OK, sorry. I'm still pretty new to Python and programming in general. But
I would have thought that the recipe I pointed to could be used as the
basis of a script that would uniformly replace all leading tabs with a set
number of spaces, thus preserving relative indents. (On the assumption
that the code being transformed is all tabs.)

1) The conversion I need to do is the other direction spaces->tabs.

2) Simply converting all leading spaces to the right number of
tabs (unexpand knows how to do that) isn't correct. Only
the spaces that are block-indent spaces should be converted.

For example:

1 ....if (asfsadfsadf and qwerqwrwer and
2 ........(asdf or qwer)):
3 ........doThis( )
4 ........doThat( )

Let's say we want to convert the lines above (indented with
groups of 4 spaces) into tab-indented code. In line 2, only the
first 4 spaces should be converted into a tab. The second set
of 4 spaces aren't block-indent spaces they're visual alignment
spaces used to line up the sub-expression, and they need to
remain 4 spaces regardless of the indentation level chosen by
the person viewing the tab-indented code.
Still, the approach of replacing only leading tabs seems to me
like it would work. I did up a script and from my testing it
appears to preserve block structure. But I hesitate to post
code; one gaff a day is enough ;-)

If there's a subtlety that is blowing past me in my
newbieness, enlightenment would be appreciated. On the other
hand, if you'd like to see the code, I'd be happy to share.

The problem is that sometimes lines contain leading spaces that
shouldn't be converted to tabs.

--
Grant Edwards grante Yow! All right, you
at degenerates! I want this
visi.com place evacuated in 20
seconds!

[Brian van den Broek]

Grant Edwards said unto the world upon 28/07/2004 19:15:

In article <ma************ *************** **********@pyth on.org>, Brian van den Broek wrote:

"unexpand" will do dumb conversion, but what's required is
something that understands Python block syntax. Something
similar to C's "indent" program.
OK, sorry. I'm still pretty new to Python and programming in general. But
I would have thought that the recipe I pointed to could be used as the
basis of a script that would uniformly replace all leading tabs with a set
number of spaces, thus preserving relative indents. (On the assumption
that the code being transformed is all tabs.)

1) The conversion I need to do is the other direction spaces->tabs.

Doh! :-[
2) Simply converting all leading spaces to the right number of
tabs (unexpand knows how to do that) isn't correct. Only
the spaces that are block-indent spaces should be converted.

<Helpful explanation snipped>

If there's a subtlety that is blowing past me in my
newbieness, enlightenment would be appreciated. On the other
hand, if you'd like to see the code, I'd be happy to share.

The problem is that sometimes lines contain leading spaces that
shouldn't be converted to tabs.

Hi Grant,

thanks for the explanation. Since you probably have better things to do
than play "spot the newbie's confusion" and I am fresh out of feet to
stick in my mouth, let's leave it there ;-)

Best,

Brian vdB

[Grant Edwards]

On 2004-07-28, Brian van den Broek <bv****@po-box.mcgill.ca> wrote:

The problem is that sometimes lines contain leading spaces that
shouldn't be converted to tabs.

thanks for the explanation. Since you probably have better
things to do than play "spot the newbie's confusion" and I am
fresh out of feet to stick in my mouth, let's leave it there
;-)

We were all newbie's at everything sometime and are newbies at
something all the time. ;)

--
Grant Edwards grante Yow! Were these parsnips
at CORRECTLY MARINATED in
visi.com TACO SAUCE?

[Tim Peters]

[Grant Edwards, wants to convert spaces to tabs]

...
2) Simply converting all leading spaces to the right number of
tabs (unexpand knows how to do that) isn't correct. Only
the spaces that are block-indent spaces should be converted.

....

reindent.py is in your Python distribution, and is the state of the
art for "intelligen t" conversion of tab-infected files to
space-celebrating ones. I understand that's not the direction you
want, but it is the *code* you want to start from. Doing a good job
on this is harder than anyone believes until they've failed at least
once, and the problem is indeed dealing with "semantical ly
insignifcant" whitespace in a pleasant way, trying to guess the
author's intent about visual appearance. reindent.py is aware of the
*semantic* indentation level of each line, and you could fiddle its
internals to convert just the semantically significant leading spaces
to hard tabs.